Joon-su is a popular but rebellious 19-year-old. One day, his parents give him an ultimatum, leaving him alone in the house to rehabilitate his life. He doesn't mind the independence until a six-month-old baby Woo-ram is delivered to his doorstep. He has no choice but to care for Woo-ram and attend to his demand for breast milk. Where can he find a good nanny?

19岁的青春期问题少年俊秀（张根锡饰）是个上起课来就呼呼大睡，打起架来就精神百倍以一敌十七的家伙，突然有一天，他遇见留下10万韩元就离开家里 的父母的只有6个月大的小男孩乌兰（Mason饰）。必须每天按照学校规定不能翘课，没有照顾婴儿的经验的俊秀烦恼得恨不得自己是女人或有分身之术，乌兰 的“粮食问题”成为目前最棘手的事情：俊秀开始四处寻找天然的母乳，两人开始了“离谱”而惊险妙趣不断的同居生活，过程中笑料百出……