After eight months of dating, realtor and aspiring developer Peter Klaven(Paul Rudd) asks entrepreneur Zooey Rice(Rashida Jones) to marry him, she says yes. It isn't until then that they both realize that while Zooey has a plethora of female friends to populate the wedding party - with Denise(Jaime Pressly) and Hailey(Sarah Burns), her business partners, being her closest friends - Peter has no real male friends. Even within his family, he is closer to his mother, Joyce - who Zooey believes is his best friend - than he is to his father, Oswald, or younger gay brother, Robbie. To overcome the problem of who will be his best man, Peter goes on a quest for a bromance. This task is difficult for unassuming Peter, who really doesn't know how to deal with men in a true friendship. After several missteps with potential bros, Peter finally meets financial investor Sydney Fife at one of his open houses. Sydney is straightforward and perceptive but an overgrown adolescent in his personal life. Still, Peter and Sydney bond. As Sydney becomes a bigger part of Peter's life, Peter has to figure out how to balance his life with Zooey and his life with Sydney, the two who may have their own issues in what the other means in Peter's life.