He has a formula, but hasn't got a clue.
There is only a small window of time for a man to meet the right woman, if she's too young, she's too naive. If she's too old, she's too jaded.
This is the Window Theory, according to Ethan "Hump" Humphries, a 25-year old man suffering from a classic case of Peter Pan syndrome - he refuses to grow up! In the seven years since graduating from high school, his sole accomplishment is being able to get into any club or party in Los Angeles. Supported by wealthy parents, he works out, parties, and brings home a different girl every night. And he couldn't be happier.
Things change, however, when Ethan receives a call from his drunken friend Brad, who accidentally spills the beans about their childhood friend Jeff's wedding. Feeling left out, Ethan immediately flies home for the ceremony, only to discover that Jeff is marrying Ethan's high school sweetheart, Stephanie.
Sliding into regression, Ethan tries to recreate his high school glory days with his friends. Although is relationship with Jeff is in shambles, Ethan focuses his efforts on getting Stephanie back before it's too late. But is he really in love with her, or simply trying to hold onto the past?
to re-evaluate what matters most in life, Ethan begins to understand that he has a lot to learn about friendship, love and growing up. Ethan may think that women only have a small window of desirability, but if he doesn't clean up his act soon, his window of opportunity is about to slam shut.