Martin Blank is a hitman for hire. When he starts to develop a conscience, he botches a couple of routine jobs. On the advice of his secretary and his psychiatrist, he decides to attend his ten-year high school reunion in Grosse Pointe, Michigan.

When record store owner and compulsive list-compiler Rob Gordon gets dumped by his long-time girlfriend, Laura, because he hasn't changed since they met, he revisits his top five breakups of all time in order to figure out what went wrong. As he examines his failed attempts at romance and happiness, the process finds him being dragged, kicking and screaming, into adulthood.