Sutter Keely (Miles Teller) is a person who lives in the now, considering, in his opininon, he wants to be there or because he doesn't see himself having a future. His ex girlfriend Cassidy (Brie Larson), his currently girlfriend Aimee (Shailene Woodley) and his geometry teacher Mr. Aster (Andre Royo) all attempt at one point or another to get him out neutral.
Sutter and Aimee eventually meet Sutter's father Tommy (Kyle Chandler), who happens to be an adult version of him. This results into an already questionable drinking habbit of Sutter's to become worse.
Eventually, Sutter drinking results him into having a break down in front of his mother. Sutter realizes that he has to change his ways. Sutter drives up to see Aimee in college. Aimee sees him and smiles. Whether they get back together is left to the viewer.
Thanks Michael R!