Scott Lang begins as a convict struggling to rebuild his life and reestablish a relationship with his daughter. He is also a highly educated man and a brilliant engineer, which is what makes him so good at burglary. When he reaches a point of absolute desperate conditions, he makes a wrong decision to return to his criminal ways.
However, the burglary leads him down an unbelievable path; an opportunity for redemption. Dr. Hank Pym, the inventor of the Ant-Man suit, joins forces with Scott to stop the evil Darren Cross from weaponizing his invention. Dr. Pym is one of very few people who sees value and potential in Scott enough to trust him with his greatest invention. No one else in Scott's life is willing to give him a second chance at life. A chance to make his daughter proud. A chance to be a hero.
However, Scott is not the only person in need of redemption. Dr. Pym on a journey to right his wrongs. Wrongs he can only right with the help of Ant-Man. For it is his research and technology that run the risk of falling into the wrong hands. If so, the consequences have catastrophic potential. All the more reason for Dr. Pym to find the perfect person to bear the responsibility of the suit.
The movie subtly expresses four aspects of being a proper hero.
1. The Suit: The suit is designed to shrink a person to the size of an ant. It makes the person as strong as an ant, and it is resilient to physically protect the person. The suit also includes equipment enabling the person to communicate with ants, thus making millions of allies.
2. Intelligence: Scott is a brilliant man. His experience in engineering and understanding of how things work grant him the ability to infiltrate several buildings successfully and discreetly. He is able to learn the exact timing of shrinking and regrowing. Most importantly, he knows how to improvise a solution when his suit goes subatomic, and he is nearly wiped from existence.
3. He's Disposable: Dr. Pym has a capable daughter. Why does he overlook her in favor of a stranger? She struggles to understand why her father disregards her. What she fails to realize is because he loves her that he cannot bear the thought of endangering her life. Dr. Pym has no emotional connection to Scott, which makes him a better candidate for dangerous work.
4. Heart: Scott's passion for justice is so strong that it becomes not only the cause of his earlier incarceration, but also the drive to risk his own life to save others. His love drives him to sacrifice, and that is the most heroic quality of all.
Ant-Man is unique, because it is a member of the Marvel franchise. At the same time, it stands alone. As unlikely as it appears, I would love to see more of him in upcoming Marvel films.