Jeff Bauman is a Boston man working in a corporation and lives in a small apartment with his alcoholic mother, Patty. One day, at a local bar, Jeff meets his ex-girlfriend, Erin, who is attracted by his kindness and charm, but he is frustrated at the height of his lack of involvement. After learning that Erin is running the Boston Marathon to raise money for a hospital he works for, Jeff persuades every bar client to donate money to that cause and promises Erin that he will wait for the line of arrival.
On the Day of Marathon, Jeff struggles to arrive in time on the finish line, but manages to make it to the limit. When she approaches, a bomb is detonated in the spot where Jeff is. After being urgently taken to the hospital, both of Jeff’s feet must be amputated above the knee. When he recovers his knowledge, Jeff tells his brother that he saw the one who put the bomb shortly before the explosion.
Patty calls the FBI, and Jeff gives them the description of Tamerlan Tsarnaev. Tsarnaev is captured by local authorities a few days later, and Jeff is considered a hero. Jeff strives to adapt to his new life of invalidity, but also to his newly-acquired fame. Patty gets some interviews, and Jeff is constantly surrounded by reporters during her retirement sessions, which dislikes Erin, who has since reappeared with him.