Graviton

"Graviton" is the second episode of the first season of ABC's The Avengers, and the second episode of the series overall. The episode was directed by Joss Whedon and written by Joss Whedon, Jed Whedon & Maurissa Tancharoen. It first aired on October 2, 2014 and was viewed by 15.86 million U.S. viewers live.

Synopsis
When Loki recruits Dr. Franklin Hall/Graviton, a superpowered criminal in S.H.I.E.L.D. custody, the Avengers must work together to stop him. Meanwhile, Bruce tries to figure out what he did wrong.

Plot
Nick Fury, Maria Hill, Clint Barton, and Hank Pym manage to convince Thor to help them stop Loki instead of doing it on his own. They return to S.H.I.E.L.D., where they learn of Bruce Banner's transformation and escape. Pym begins to look in Banner's office to find clues of what he did. Fury learns of the alert at the Raft and realizes Loki is after Graviton.

At the Raft, Loki convinces Franklin Hall/Graviton that he is an alien and wants his help to invade Earth. Loki promises him the honor of killing Fury, and Graviton agrees to join him. Loki breaks him out and they escape.

At NYU, Banner returns to his human form, now naked. He sneaks into his office at NYU, where Betty Ross catches him. The two begin to have sex, but Banner starts to transform, causing him to stop it. Ross threatens to get him fired, revealing her father is the reason Banner has the job. This causes Banner to become more angry and transforms into the Hulk in front of her.

Pym discovers that Bruce was recreating the Super-Soldier serum. This cheers them up, as they now know it was Banner that did it to himself, not Loki. Thor decides to take a team out to find Loki, but Fury warns him against it. Despite this, Steve Rogers and Tony Stark join Thor as they leave. Fury has Hill use security footage of the Raft to find out where they went. Natasha Romanoff and Barton decide to look for Banner.

Loki and Graviton return to the Skrull mothership, where Graviton trains. Loki learns that the Cosmic Cube could open a portal directly from the mothership to Earth, so that they wouldn't have to go into Earth's orbit. Loki prepares the portal.

Banner goes on a rampage throughout New York, and the police are unable to stop him. Romanoff and Barton find Ross, who reveals what happened. Romanoff calls in S.H.I.E.L.D. backup, which arrives just in time. Banner transforms back into his human form, though he is unconscious. S.H.I.E.L.D. take him in. The media labels him as "The Hulk".

Stark, Rogers, and Thor search the woods for Loki, but have no luck. However, they find a dark cave, where a blue light begins to show. Suddenly, Skrulls appear and attack them. Thor realizes Loki is using the Cube as a portal to get the Skrulls to Earth. The three heroes decide to return to S.H.I.E.L.D., but Thor manages to close off the portal for a short time. However, as they walk away, Stark is revealed to be a Skrull in disguise.

On the mothership, Loki is angered that Thor discovered their plan. Graviton, getting bored, decides to return to Earth, but Loki pleads with him to stay until their plan can go into action. Graviton reluctantly agrees, but secretly steals the Cube and leaves.

Back on Earth, Banner awakens in a cell and promises he cannot control the Hulk. Hill demands he get a grip on it, but Banner realizes that it only comes out when he gets too much adrenaline. Pym, hearing this, decides to work on an injection to lower his adrenaline if he ever gets too much and begins to transform.

In the woods, Rogers and Thor realize Stark is acting different and Thor asks him about his childhood. When Stark cannot answer, Thor kills him, shocking Rogers. However, Stark's body quickly returns to a Skrull. Thor reveals that Skrulls can access recent memories of their disguise, but nothing too far back. They return to the cave, where they realize Stark must have taken the portal.

On the mothership, Stark is hiding in the storage unit. However, when Loki comes in, Stark attacks him. The two get into a fight, which ends with both realizing Graviton is gone, and so is the Cosmic Cube.

On Earth, Graviton arrives and uses his abilities, along with the Cube's, to terrorize New York City. Pym and van Dyne take him on, but Fury insists they need more. Banner convinces Hill to let him transform into the Hulk to take on Graviton. Hulk and Graviton fight, and the latter loses the Cosmic Cube. Loki and Stark return and the former almost gets the Cube again, though Thor and Rogers stop him. Graviton is defeated and taken into custody, while Loki escapes, though without the Cube.

Graviton is taken to an Asgardian prison in secret, with only Fury and Thor knowing. Banner is able to control the Hulk more, though he still attempts to stay in his human form. The Avengers stay together to stop Loki, as he and the Skrulls are still out there.

Hill and Fury meet in secret, where Fury asks Hill if Rogers knows. Hill tells him she has managed to keep him away from anything related to "her".

Starring

 * Matt Bomer as Tony Stark
 * Justin Hartley as Steve Rogers
 * Matt Barr as Thor
 * Matthew Gray Gubler as Bruce Banner
 * Josh Holloway as Hank Pym
 * Evangeline Lilly as Janet van Dyne
 * Jenna Dewan Tatum as Natasha Romanoff
 * Jensen Ackles as Clint Barton
 * Morena Baccarin as Maria Hill
 * Damon Wayans as Nick Fury

Guest Starring

 * Matt Smith as Loki
 * Kat Dennings as Betty Ross
 * Garret Dillahunt as Graviton