4.2. Ant-Man

In 1989, Hank Pym resigns from S.H.I.E.L.D after discovering that Howard Stark has been attempting to replicate Pym's shrinking technology, which he believes is too dangerous to risk falling into the wrong hands.

In the present, Pym's estranged daughter, Hope van Dyne, and his protege, Darren Cross, have forced him out of Pym Technologies. The ignominy is worsened when Cross unravels his own project; the Yellowjacket Suit, based on Pym's original technology.

Scott Lang has just been released from San Quentin Prison, after serving three years for burglary. He reunites with his former cellmate Luis, and Luiz's partners Kurt and Dave, who offer him a part in a heist. Scott refuses, as he intends to go straight. On returning home, he learns that his ex-wife is engaged to a police officer. His wife tells him he cannot see their daughter anymore if he does not provide child support.

Unable to find work due to his criminal record, Scott eventually accepts Luis's offer. He infiltrates the house Luiz has targetted and cracks open a safe. Instead of money, he finds something which he describes as an "old motorcycle suit". He eascapes, taking the suit back to his apartment. He starts toying with it, and ends up putting it on. Accidentally hitting a button on the suit's belt, he inadvertently shrinks down to the size of an insect and struggles to return to his original size. Terrified by this experience, he attempts to return the suit to the house he stole it from, only to be discovered by the police and arrested.

Pym, the owner of the house which Scott broke into, poses as a lawyer and smuggles the Ant-Man Suit into Scott's cell to help him break out. Although confused, Scott puts on the suit and escapes the prison with the help of a group of ants.

Scott discovers that Pym manipulated him, using Luis to trick him into stealing the suit as a test. He wants Scott to become the new Ant-Man and steal the Yellowjacket suit, which Pym considers to be extremely dangerous. Pym asks Hope to spy on Cross, and she reluctantly. Meanwhile, Hope and Pym trail Scott to control the Ant-Man suit, and to control ants.

Pym sends Scott on a mission to retrieve a device from the New Avengers Facility. The facility was previously a Stark Industries warehouse, and some of Hank's old experiements are still in storage there. Scitt succeeds on the mission, despite getting into a fight with Falcon.

Frustrated by her resentment of him, Pym finally tells Hope the trust about her mother's death. Janet Van Dyne had been his partner at S.H.I.E.L.D. using the code-name Wasp. During a mission, she had shrunk herself too far in order to disarm a Soviet Union missile, loosing control of her size and shrinking down into the Quantum Realm. He admits that the reason he had given the suit to a stranger, rather than to her, is because he is afraid of loosing her the same way

Cross perfects the Yellowjacket suit, and invites Pym to the unveiling. While the product reveal is taking place, Scott, along with his crew and a swarm of ants, infiltrates the building. However, Scott is captured by Cross who was expecting something of the kind. Cross then sells both the Ant-Man and Yellowjacket suits to the HYDRA and the Ten Rings. Scott breaks free from his trap, fights the HYDRA agents, and chases after the escaping Cross. In the chaos, Mitchell Carson escapes with Cross's unstable formula. The explosives detonate, imploding the building into the Quantum Realm.

Cross dons the Yellowjacket suit. Lang traps Cross in a bug zapper, but before he can sabotage his suit, he is tased and arrested by his ex-wife's fiancé, Jim Paxton. Cross escapes. He holds Scott's's daughter, Cassie, hostage to lure Scott to him. They fight but Scott is loosing. As a last effort, Scott shrinks to a subatomic size to finally penetrate and sabotage the Yellowjacket suit. They both shrink uncontrollably through the quantum realm. Cross eventually implodes, due to his suit being damaged by Scott. Scott, fighting unconsciousness, finds the will to escape. He puts a disc with enlarging Pym Particles inside the suit's regulator and switches it back on, successfully reverting to his original size.

Witnessing Scott's heroism, Paxton covers up for him. Scott remembers nothing of his experience in the Quantum Realm. Pym believes the human mind might not be able to process it. However, as Scott had survived it, he begins to suspect Janet might still be alive.

Pym offers the upgraded prototype of the Wasp Suit to Hope, to which she replies, "it's about damn time".