The story follows Hank Pym, a scientist who, years ago, discovered Pym particles, capable of shrinking people. Inspired by his studies of ants, he created a suit that allowed him to change size and communicate with them, becoming the hero Ant-Man. This happy period comes to an end when his fiancée, Maria Trovaya, is murdered. Consumed by guilt for not protecting her, Hank abandons the suit and his heroic identity.
In the present, Hank works with Vernon van Dyne, but must deal with Janet, Vernon's seductive and provocative daughter. When a news report reveals that a party at the van Dyne house was invaded by armed criminals, Hank doesn't hesitate to become Ant-Man again to save them. After the rescue, he believes he has definitively ended his career as a hero.
However, SHIELD discovers his past as Ant-Man and blackmails him into facing a new threat: Harvey Rupert Elder, the Mole Man, a former colleague who plans to attack the surface seeking revenge. Even though he's forced to, Hank realizes he enjoys being Ant-Man again and decides to continue.
