當小咖音樂人彼得的電視明星女友Sarah Marshall甩掉他和搖滾明星Aldous Snow 在一起後，彼得的世界天崩地裂。這位菜鳥音樂人決定到夏威夷度假，希望能忘懷和前女友的分手傷痛。但他並不知道Sarah也到同一個地方度假，並且跟新男友一起同行，兩人飯店房間就在彼得的房間隔壁。彼得將面臨更大的打擊，而Sarah的人生也將出現轉變。
Peter's world comes crashing down after his TV star girlfriend, Sarah Marshall, dumps him for rock star Aldous Snow. This aspiring musician decides to take a vacation to Hawaii to deal with his break up with his ex-girlfriend. Little does he know, that Sarah is traveling to the same resort and she is bringing along her new boyfriend as well. Peter goes into a further emotional tailspin while Sarah's life also takes a turn.
