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This article describes the Portal 2 storyline, chapter by chapter.

Portal 2 almost directly follows the events of Portal from Chell's perspective, although being set between 50 to 50,000 years after the events of Portal. The co-op portion of the game follows ATLAS and P-body, whom GLaDOS accompanies through the Cooperation Testing Initiative.

The single-player campaign is set directly after Portal and Portal 2: Lab Rat, and right before the cooperative campaign.

Single-player campaign[]

Chapter 1: The Courtesy Call[]

Relax chamber 1

Inside of Chell's Relaxation Chamber.

Relax chamber 1 later

The inside of Chell's Relaxation Chamber after she is woken up.

Glados awakens

Chell, Wheatley, and the newly-reawakened GlaDOS.

Fifty days after she is put in stasis, Chell is awakened by an unidentified announcer. In compliance with "state and federal regulations," Chell is instructed to perform a mandatory physical and mental wellness exercise which is used to teach the player the standard controls. Chell is then instructed to return to bed.

Between 50 and 50,000 years later (the exact time is never made clear), Chell is awakened again. During this second awakening, the announcer glitches saying that they "have been in suspension for..." followed by a glitched message repeating nines. Afterwards, Chell meets Wheatley for the first time. Chell learns that the facility's reserve power has been lost and is instructed to prepare for reactor core meltdown. Wheatley, fearing he will be blamed by "management" for the incident, plans to escape. He smashes the chamber through a wall and tells Chell to look for "a gun that makes holes." The Aperture Science facility is overgrown and badly damaged. During the escape attempt GLaDOS is accidentally reawakened by Wheatley, who is separated from Chell and GLaDOS promptly resumes forcing Chell to complete test chambers.

The test chambers and Central AI chamber are the same from Portal, albeit heavily damaged and decrepit.

This chapter includes:

Chapter 2: The Cold Boot[]

Old test chamber 01 GlaDOS' testing track Portal 2

A ruined Test Chamber 01.

GLaDOS introduces new tests. They primarily include Thermal Discouragement Beams and Aerial Faith Plates. This chapter includes GLaDOS' Test Chambers 1 to 8.

Test chamber 1 is the first chamber to use the Thermal Discouragement Beam alongside with portals. GLaDOS claims to need to start the facility back up while she performs the test, and then tells Chell to pace herself because of a numerous amount of tests.

Test chamber 2 introduces Discouragement Redirection Cubes as well as the ability of the cubes to press buttons alsongside of redirecting lasers. Upon completing the test, GLaDOS tells Chell that the test said that "she was a horrible person".

Test chamber 3 introduces Discouragement Redirection Cubes alongside with portals to complete the test, alongside with being the first chamber to use 2 lasers. After the test, GLaDOS congratulates Chell on "beating the odds" and not being extremely skinny after emerging from suspension.

Test chamber 4 introduces the ability for lasers to activate moving platforms, as well as the feature of Chell needing to jump over the beam so that she doesn't get pushed off of the platform. Before the test, GLaDOS clears away some fallen panels that block the way and tells Chell to go slowly. At the end, GLaDOS tells Chell that she "doesn't have to go that slowly."

Test chamber 5 introduces the Aerial Faith Plates. In this chamber, Chell needs to time her jumping on a Faith Plate to the cube bouncing on a Faith Plate so that she gets the cube.

Test chamber 6 introduces "Advanced Aerial Faith Plates", which is a conjunction of Faith Plates and portals to get Chell to a button and to maneuver the cube to the button. GLaDOS indirectly calls Chell "smelly garbage standing around and being useless", which she apologizes for (sarcastically) at the end of the test.

Test chamber 7 is the only chamber in the game to have the Companion Cube, which is not as heavily stressed upon as in Portal. In fact, GlaDOS fizzles the cube several times before she lets Chell use it to solve the test. The chamber requires Chell to fling to activate a door. The testchamber also has a broken emancipation grill, which means that Chell can smuggle the Companion Cube into the exit. If Chell does this, then GLaDOS fizzles the cube.

Test chamber 8 introduces the concept of fizzlers mid-level, in which Chell has to portal through a small gap and use a redirection cube to shoot a laser through a fizzler. GLaDOS mocks Chell once again before leaving, saying that the turbines have broken down. It is the last chamber of the chapter.

Test Chamber 04 P2

A ruined Test Chamber 04.

Chapter 3: The Return[]

Chell is put through more tests. The Hard Light Bridge and turrets are introduced.

Meanwhile, Wheatley formulates a plan to escape. GLaDOS spouts out information regarding the building, as well as attempting to trick Chell once more. GLaDOS also mentions of finding two people with Chell's last name, coincidentally a man and a woman (presumed to be Chell's birth parents).

This chapter includes GLaDOS' Test Chambers 9 to 17.

Chapter 4: The Surprise[]

Chell is given a "surprise" as hinted by GLaDOS, which is the complete absence of one, except for a puff of confetti.

Meanwhile, GLaDOS once again attempts to make Chell stop by making her feel bad, especially now GLaDOS decides to include Chell's unknown parents into their conversations. She decides to "call" Chell's parents, only to fake a voicemail message saying that her parents don't love her.

This chapter includes GLaDOS' Test Chambers 18 to 21 out of 22 total. (Wheatley breaks in at 21.)

Chapter 5: The Escape[]

Potatos wheatley

The power-mad Wheatley transferring GlaDOS into a potato battery.

Before GLaDOS can kill Chell, she and Wheatley escape. GlaDOS attempts to lure Chell to her death by leading her into a misleadingly easy test chamber. If the player chooses to enter, the walls will close in and GlaDOS will activate the neurotoxin, killing them. Otherwise, the escape will continue as normal. They eventually sabotage GLaDOS' turret and neurotoxin manufacturing facilities before confronting GLaDOS. Chell and Wheatley force a core transfer on GLaDOS so that Wheatley can take control of the facility and he and Chell can escape. GLaDOS' head is abandoned on the floor, and Wheatley—manically happy with his newfound competence—activates the lift to let Chell leave.

Unknown to he or Chell, however, the body which affords Wheatley this competence is fully instilled with a will and a set of goals of its own, and as its programming aggressively subsumes Wheatley's better nature, he becomes reluctant to leave it. Uncertain what he is feeling, he projects the source of this uncertainty onto Chell; he asks why "(they) have to leave right now" after "(he) did all this." Wheatley's mood is darkened further when GLaDOS speaks up, stating that he never did any work at all. She spitefully praises Chell to Wheatley, and his insecurities—hinted at before—blossom into egotism. He attempts to assert his superiority over GLaDOS—by isolating her personality to a miniature core dependent on a potato battery for power—and resentfully berates the mute Chell for "bossing him around."

As he continues his tirade, GLaDOS realizes that she has met him before. She recalls her distant past, where Aperture Science created Wheatley with the express purpose of impairing GLaDOS with self-destructively stupid ideas. Finding herself once again incapacitated by Wheatley, GLaDOS bitterly abuses him as "the moron they built to make (her) an idiot." Wheatley is humiliated and furious. He throws GLaDOS into the lift with Chell and beats the lift into the floor of the control room, until—unexpectedly—it detaches from its station, and plunges into the bowels of Aperture Laboratories.

Chapter 6: The Fall[]

Chell and GLaDOS fall down the disused length of what clearly used to be a much larger elevator shaft. At fully four kilometers deep, the fall gives the two plenty of time to come to terms with their new situation in regards to each other. GLaDOS is unenthusiastic about their chances of surviving their trip underneath the laboratories; she herself is unaware of how far down Aperture Science really goes and has no idea what to expect.

Chell's fall is finally broken by layers of planking, lain down at some time in the past, either because the area was abandoned, or it was to stop debris from injuring anyone below the mouth of the shaft. The wood is rotten and soft, and the rest of the impact is absorbed by Chell's long-fall boots, leaving her concussed but, fortunately, not fatally injured.

After a short space of time, Chell regains consciousness, and is greeted with the inexplicable sight of GLaDOS being menaced by a large crow. A long splinter of metal from the casing of the elevator has speared GLaDOS potato—and has prevented it from smashing on the packed gravel floor—but it has also brought the potato to the notice of the crow. The crow abducts the potato, with the AI still attached to it, and flies off.

Chell is left alone to wander Test Shaft 9 from the 1950's, back when Aperture Laboratories was instead known as Aperture Science Innovators. Chell is guided by pre-recorded messages by Cave Johnson (the former CEO of Aperture Science) and occasionally, his assistant, Caroline. Chell activates the flow of the Repulsion Gel, and begins testing in the first Enrichment Sphere, where the Repulsion Gel, the first design of boxes, buttons and switches is shown. She makes it through the 1950's testing track, and heads up to the 1970's one.

Chapter 7: The Reunion[]

As Chell is trying to find her way into the 70's testing track, she manages to find GLaDOS being eaten by a crow. With no other choice, Chell skewers GLaDOS onto her Portal Gun and continues through the Johnson-era test chambers with the AI in tow. She activates the Propulsion Gel flow and uses both Repulsion and Propulsion Gels to solve the test.

Meanwhile, ancient recordings of Cave Johnson's self-confident rambling continue, as he relates anecdotes, argues with his staff, and exhorts the test subjects to keep going. Then, for first time since Chell locates GLaDOS, he addresses the recorded ghost of Caroline, and GLaDOS speaks—blurting out the words "Yes sir, Mr. Johnson!" before she can understand what she is doing.

GLaDOS is panic-stricken, and, in her heightened emotional state, overdraws from her fragile potato battery, causing her to hard-shutdown and crashing her system. Chell is again left to traverse the old testing areas alone.

As Chell makes her way up the condemned Enrichment Spheres, she activates the flow of a third gel, Conversion Gel. A subdued GLaDOS comes back online, and the two quietly bear witness to the fact, revealed through Cave Johnson's increasingly bleak recordings, that Aperture Science lost money over the years, going from using Olympic stars and astronauts as test subjects to homeless people, and eventually just using their own employees. GLaDOS also feels that she "knows" Caroline, and must've realized she was Caroline 1. The quality of the test chambers falls dramatically as the construction dates advance. Cave Johnson—still making recordings in the past—is now extremely ill from moon rock poisoning. We learn that, and Cave feebly confides in the recordings that he has set all his scientists to the task of storing a human consciousness in a computer.

He states that—if he dies before they make it a feasible procedure—that he leaves the entire facility to Caroline and says that she is to be uploaded into the system, instead, whether she wants it or not.

Chell connects the last two experimental fluids to the uptake valves located at the twin of the first quarantine hatch, this one located at the top of the condemned section. GLaDOS quietly says goodbye to her old boss. as it is implied that GLaDOS is in reality, Caroline uploaded to the machine, with her old memories suppressed.

Chapter 8: The Itch[]

Chell and GLaDOS return near the surface to Wheatley's redesigned Enrichment Center, while making the gels available in the Enrichment Center. Wheatley has taken control, but in his incompetence has failed to maintain the facility's nuclear reactors which are now in meltdown. Instead of properly maintaining the facility, Wheatley has been busy with his own creations such as the cube-turret hybrid known as "Frankenturrets" by developer commentary.

GLaDOS attempts to destroy Wheatley with a logical paradox, but fails due to Wheatley's already-poor grasp of logic. The mad AI forces Chell to go through his own ineptly-designed test chambers stolen from GlaDOS' collection. After a few tests, Wheatley's quest for test-induced euphoria forces him into giving Chell more and more dangerous tests. Eventually, he plans to give them both a "surprise".

Chapter 9: The Part Where He Kills You[]

After several tests, Wheatley finds out about the Cooperative Testing Initiative 2 and takes it upon himself to kill the two. Chell manages to escape thanks to her skill with the portal device and a timely splatter of Conversion Gel.

Wheatley attempts to stop them using a series of ill-executed traps, (poorly aimed Crushers, mistakenly using Defective Turrets, lack of forethought, and even trying to talk Chell into killing herself) which do nothing to hamper Chell's progress.

As they make their way through the maintenance areas, the two come across a cache of un-incinerated corrupt personality cores. GLaDOS makes a plan to force another core transfer in order to return back to her original body, as well as making a deal to release Chell once they do so. Upon reaching Wheatley's chamber, a timed boss battle ensues. Chell redirects bombs to Wheatley as GLaDOS delivers corrupt cores. After attaching the three cores, Chell increases Wheatley's corruption to one hundred percent. A core transfer takes place but results in another stalemate. Chell reaches for the Substitute Stalemate button, but Wheatley expected this and placed bombs as booby-traps.

Chell gets thrown across the room as the reactor meltdown enters its final phase, shaking the chamber apart. The Moon appears through a breach in the roof, allowing Chell to shoot a portal at its surface at what is likely the Apollo 17 landing site at Taurus-Littrow (Cave Johnson said prior that lunar dust was an excellent portal-conducting surface). The vacuum of space sucks Chell, Wheatley, the Portal Gun, Rick the Adventure Core, and the Space Core through, as Chell hangs onto Wheatley's tethered core to survive. Unseen, GLaDOS successfully performs the core transfer and stabilizes the reactors. She knocks Wheatley out into space and drags Chell back to safety before closing the portal.

Some time later, Chell wakes up in an elevator, as GLaDOS, ATLAS (Blue) and P-body (Orange) greet her. GLaDOS tells her that "being Caroline" taught her a valuable lesson - that Chell was her best friend. She says she also learned where Caroline lives in her brain, and then promptly claims to have deleted that part. Now back to her usual antagonistic self, GLaDOS concedes that killing Chell has proven to be difficult, and her life was a lot easier before Chell entered it, as well as calling her a "dangerous, mute lunatic". Therefore, she gives Chell her freedom, on the condition that she doesn't come back.

As the elevator rises, an army of turrets sing an opera for Chell as she departs. After finally reaching the surface, Chell steps out from the elevator and into a golden wheat field. Suddenly, Chell's Companion Cube from the previous game, covered in soot from the incinerator, flies out of the elevator behind her and the door slams shut.

During the credits, GLaDOS sings a song about the events of Portal 2, claiming that while she used to want Chell dead, now she only 'wants her gone'. However, the lyrics of the song hint that GLaDOS' feelings about Chell may be slightly more conflicted than she'd like to admit, and it appears Caroline may still have a place in her mind.

After the credits, the picture zooms out and then it's possible to see that the credits were displayed in space on one of the computer monitors used in the observation rooms of various test chambers. Wheatley and the Space Core are floating around. Wheatley then gives a monologue (even though he is interrupted several times by the Space Core), saying that if he could see Chell again, he would apologize for being so bossy and monstrous to her. He then says "the end," and the scene fades into the main menu, where Wheatley and the Space Core are still in space in the background.

Footnotes: 1) GLaDOS does seem to realize she was Caroline. She says: "Caroline... Caroline... WHY do I know this woman?! Did I kill her, or-- oh my god... look, you're.. doing great. Do you think you can handle these tests on your own for a moment? I need to think..." | 2) In the game, Wheatley says: "You've probably figured out by now, but I don't need you anymore. I've got two models in the back built specifically for testing." GLaDOS, right after Wheatley says that, says: "Oh no, he's found the core cooperative testing initiative. It's something I came up with to phase out human testing just before you escaped." She's presumably talking about P-Body and Atlas.

Cooperative Campaign[]

The co-op campaign is set after the events of Portal 2's single player campaign. In it, the two testing androids ATLAS and P-body of the Cooperative Testing Initiative carry out a series of tests in six different courses, each consisting of about eight or nine chambers. At the end of each course, GLaDOS sends the androids outside of the testing chambers and into the facility itself, claiming their help is needed to retrieve several Compact Discs "innocently" left lying around by the humans. In reality, she appears to be using the androids to help her gain control of the facility and gain information on "Area 219.32". After each out-of-chamber task, both androids are self-destructed and then reassembled in the Hub.

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Calibration Course[]

The initial cooperative course whose main purpose is to 'calibrate' ATLAS and P-body for each other, as well as their own controls. During this course, GLaDOS implies the idea that most of this course is a competition of who is faster, as well as initiating her general attitude of creating friction between the two.

Team Building[]

ATLAS and P-body are put through a series of simple tests, designed to promote cooperation and teamwork through the use of Super Buttons and Thermal Discouragement Beams. The final test sends them down to the basement of the facility to activate a targeting computer, which locates a small group of objects.

Mass and Velocity[]

This test course focuses on advanced "flinging" techniques, teaching ATLAS and P-body to not only form complex chains using all of their portals, but also timing to allow one to catch an object mid-fling when it is dropped by their partner. The final test involves retrieving a set of blueprints outside of test areas, which GLaDOS states are of no concern to the androids.

Hard Light Surfaces[]

The next test course involves the Hard Light Bridges, teaching ATLAS and P-body to use them as both platforms and shields. The final test has them download a security code which GLaDOS attempts to drown out with a series of "blah" noises.

Excursion Funnels[]

The Excursion Funnel test course, as with the previous ones, teaches the cooperative use of funnels and their reversal function. The final test mixes the use of the funnels and Hard Light Bridges as shields in order to reach a power station, which is activated to provide power to the final course.

Mobility Gels[]

With the previous courses finished, GLaDOS can now access a vault in the lower levels which contains hundreds of human test subjects. She has determined that, given their inability to die, ATLAS and P-body just aren't the same as human test subjects. They are sent to open the vault. These final chambers take elements from all the previous test courses while adding the Aperture Science Mobility Gels as an additional element. In particular, the creative use of Hard Light Bridges and Excursion Funnels in conjunction with the gels is a necessary aspect of completing the test. Upon reaching the vault, ATLAS and P-body open it by making similar gestures to the camera installed on the lock. GLaDOS claims to have more work for them as she destroys them. As the credits roll, GLaDOS scans the identities of the test subjects and makes remarks about them, both positive and negative, though in the end the comments are apparently all directed at one subject.

Portal 2: Peer Review[]

Art Therapy[]

GLaDOS rebuilds ATLAS and P-body, claiming that 100,000 years have passed since the conclusion of the 'Mobility Gels' course. She also claims (unconvincingly) that all of the humans are still alive. She guides the two of them through a new set of courses (which are supposedly designed to be art exhibitions), though a number of mechanical failures occur, which GLaDOS attempts to cover up.

At the end of Chamber 4 the disassembly machinery fails, forcing ATLAS and P-body to make a detour through an incomplete test track. GLaDOS admits that she has been lying and reverses her original claim of the humans being fine, revealing that she has already killed them all during testing. She also comes clean that it has only been a week since the humans were "rescued," not 100,000 years.

GLaDOS believes that "she" has returned and has gained control of an old mainframe chassis, posing a threat to the facility. ATLAS and P-body spend the remaining chambers being "trained" as killing machines, though this merely involves solving further tests and being plied with generic insults. In the final chamber, GLaDOS informs the two that the reassembly machines have broken down and that if she doesn't regain control, their next deaths will be permanent.

The robots reach the chassis, but find that it is being controlled mindlessly by a crow nesting. Despite GLaDOS' calls for a retreat (due to her phobia of birds following her experiences as a potato), ATLAS gets the bird from the control panel and P-body manages to lock it out of the facility. GLaDOS then notices that the crow had been harboring three eggs, which she hatches in an "oviparous warming vault," planning to breed the chicks as "little killing machines". This reinforces speculation of using birds as test subjects as seen in Portal.


  • During the prologue in the relaxation chamber, the first time the player looks at the art on the wall it shows a cabin and some mountains. After waking up for the second time, if the player looks at the art, a moon will be painted on it, effectively foreshadowing the ending sequence. Also, still after Chell's second awakening, a howling wolf can be seen to have appeared at the bottom of the wallpaper next to the fridge; it was not there before. It is not sure what this means, except that it adds to the ominous feeling surrounding the events.
  • A developer commentary node near the beginning of the game states that there is an impossible space in the game. This space can be found in Chapter 9, being in the form of Test Chamber 75 where the failed Turret ambush takes place.
  • During the boss battle, it does not matter what color or where the player shoots the portal on the moon. It will always display as the same place on the moon, and an orange portal will always appear under Wheatley.
  • When the player portals to the Moon and sees the Earth, the oceans appear to be at modern day levels, despite the fact that the Combine drained the earth's oceans during their occupation. This could hint that they were defeated and retreated from Earth, (as the game takes place many years after the events of their invasion) or it could be a simple reuse of avaliable assets.
  • After Chell is dropped into the Incinerator Room by GLaDOS, she progresses through Test Chamber 19 from Portal backwards. Also, the incinerator she is dropped into is the same one that the Personality Cores are dropped into in Portal.
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