威尔(休·格兰特 Hugh Grant 饰)是一个伦敦的有钱人。他继承了父亲的遗产，终日吃喝玩乐，游戏情场。然而，他内心却有着空虚和孤独。为了能够认识更多的女人，他想到了单亲家长会。那里单亲妈妈众多，他必然能游刃有余。带着这个目的，他假扮成单亲爸爸，加入了单亲家长会。 　　马克斯（尼古拉斯·霍尔特 Nicholas Hoult 饰）的母亲也是家长会里的成员。母亲每天早晨醒来，都会开始沮丧、落泪，想自杀。马克斯家庭不幸，加上常常受人欺负，身处劣境的他寄希望于威尔，把威尔当作可依赖的对象。他经常造访威尔家，坐在威尔身边默默的看电视。起初这一切让威尔觉得十分打扰。但是慢慢的，两颗孤独的心开始找到依靠，威尔和小男孩之间的友谊渐渐升温。Twelve year old Marcus Brewer lives with his chronically depressed single mother, Fiona Brewer. Both Fiona and Marcus beat to their own respective drummers. Marcus will do whatever he can to make his depressed mother happy, even if it causes himself grief. As such, he realizes that he is perceived as different than most kids, as even the self-professed weird kids don't want to hang out with him as he is the target of bullying. Part of the taunts against him are the fact that he sings and speaks to himself without even realizing that he is doing it. Meanwhile, thirty-eight year old Will Freeman is a slacker who has lived comfortably off the royalties of a song written by his deceased father, and as such has never had to work a day in his life. He is a solitary man who places himself as the first and only priority in life. He comes across the idea that dating single moms meets his selfish carnal needs. It is in this capacity that Will meets Marcus, as one of Will's single mother conquests, Suzie, is friends with the Brewers. Trying to escape his life but wanting Will to date Fiona, Marcus infiltrates Will's life, much to Will's chagrin. Will slowly begins to realize that Marcus is more than just a nuisance, but rather someone who needs some guidance navigating through the trials of adolescence and the trials of dealing with a suicidal mother, and perhaps he can be a small part of providing that direction. Conversely, Marcus may be able to show Will the path to becoming a real adult.