"To Steal an Ant-Man!"
Scott Lang has had a hard life. His daughter Cassie was born with a congenital heart condition that threatens her life. Mounting medical bills drove Scott to a life of crime, and subsequently, jail.
After time off for good behavior, he's out, still faced with his daughter's rapidly deteriorating health. He hears of a specialist who could save her, Dr. Erica Sondheim. When he tries to contact her, he is just in time to see her abducted and taken to Cross Technological Enterprises.
In an effort to get his daughter the help she needs, he thinks that he needs to pull one more theft to get the resources. He inadvertently breaks into the home of Henry Pym and discovers the costume of Ant Man. He steals it and uses it to get to the captive Dr. Sondheim, only to find the monstrous owner of Cross Industries, Darren Cross, standing in his path.
First appearance of Scott Lang as Ant-Man.