In one week's time Paulie (Ed Burns) will be married to his beautiful fiancée, Sue (Brittany Murphy). She's about to have a baby. But with his four groomsmen getting together for one last week of extended adolescence before the big day, it's Paulie that is going to have to grow up, something that guys find hard to do.

As he bands together with his gang of lifelong pals from the same suburban New York neighborhood – his brother Jimbo (Donal Logue), Cousin Mike (Jay Mohr), Dez (Matthew Lillard) and T.C. (John Leguizamo) – Paulie can't help but get a nagging feeling that he's about to lose some vital part of who he is.

He isn't the only one affected by the impending nuptials. Jimbo (Logue) has his own secret frustrations and resentments, and as his brother prepares to take this giant step in his life, Jimbo can't help but feel Paulie has somehow achieved everything he hasn't, and works to make sure Paulie doesn't make the mistakes he's made.