皮特（杰森·席格尔 Jason Segel 饰）是个音乐人，有个比他出色得多的女朋友莎拉·马歇尔（克莉丝汀·贝尔 Kristen Bell 饰），她是个当红电视明星。皮特对她一片痴心当牛做马，但还是惨遭她的抛弃。备受打击的皮特经历了很久的消沉，还要整天在电视上看到莎拉的各种新闻，为了走出失恋阴影，他跑去夏威夷火奴鲁鲁度假，却恰好在酒店遇到莎拉和她的新男友。皮特感觉命运在捉弄他，不过此时他邂逅了度假村服务员瑞秋（米娜·古妮丝 Mila Kunis 饰），后者美丽、热情，愿意倾听他的不幸，还带他进入夏威夷的火热生活。皮特慢慢爱上瑞秋，但是莎拉又和新男友闹分手了，似乎有意愿向皮特回头……Peter is a composer and a likable sad sack who's devastated when his girlfriend of five years, Sarah Marshall, the star of a cheesy CSI-style crime show, dumps him. He weeps, he rails, he mopes. Finally, his step-brother Brian suggests Hawaii, so Peter heads for a resort on Oahu where, as he's checking in, he sees Sarah and her new beau, Aldous, a polymorphously perverse English rocker. The weeping and moping start again, until Peter is rescued by Rachel, a thoughtful hotel clerk who invites him to a luau and to hang out. Although he constantly runs into Sarah and Aldous, Peter starts to come alive again. Will Sarah realize what she's lost, and what about Rachel?