After his involvement in Captain America: Civil War’s massive airport battle (where he fought with Team Cap), Scott Lang took a plea deal with the government so he could return home. In the original Ant-Man film, Scott’s primary motivation is being able to go back to his daughter, Cassie. That’s what made his participation in Civil War’s conflict so strange. Because he sided with Steve Rogers against the Sokovia Accords, Scott was once again on the wrong side of the law and found himself in a top-secret underwater prison.
Of course, at the end of Civil War, Rogers breached the Raft and freed his allies who were in there, including Scott. This allowed the likes of Sam Wilson to participate in the events of Avengers: Infinity War, which Ant-Man, of course, sat out. Infinity War first revealed Scott and Clint Barton struck deals in order to resume their lives as “free” men, and now we have more details about what exactly that entails.
It would appear this is going to be the source of much drama in Ant-Man and the Wasp. Scott apparently is the key to rescuing Janet Van Dyne from the Quantum Realm, so he can’t just sit this adventure out on the sidelines. Lang’s house arrest could also play into the film’s “race against the clock” set up, as the main events take place over the course of “one bad night.” Scott would probably prefer to return home as quickly as possible before any authorities realize he’s not there. That sense of urgency should help Ant-Man and the Wasp have some genuine, personal stakes. Nobody is expecting the sequel to be as grand in scope as Infinity War or even Black Panther, but director Peyton Reed seems to have cracked a way to keep tensions high throughout the story.
Of course, house arrest is about to be the least of Scott Lang’s concerns. Since Ant-Man and the Wasp takes place prior to Infinity War, the MCU has yet to feel the effects of Thanos’ genocidal snap during the standalone. Ant-Man has been seen in alleged leaked Avengers 4 artwork, so he’s going to be part of the team that tries to take down the Mad Titan once and for all. Audiences were led to believe Scott was still serving the remainder of his sentence in Avengers 3, but with half the universe wiped out and Ant-Man one of the handfuls of beings with powers, it’s possible whatever punishment he has is waived so he can fight without consequences.