Gwen, a director of television commercials, has mapped out her life in an attempt to be in control. That plan was devised as she never wants to be thrown for a curve like she was when she was thirteen when her father unexpectedly died. That plan includes being engaged by the time she reaches thirty, which is just around the corner. That engagement and imminent marriage will be ...。三年前,刘敏宇(宋承宪 饰)意外失去了自己挚爱的未婚妻,他抱着悲痛的心选择了出国留学;而那时的沈慧媛(孙艺珍 饰)是个患有先天性心脏病的安静女孩,看着别人健康的跳跃着,自己只能坐在角落。
三年后,先前接受了心脏移植手术的慧媛变得活泼开朗,也有了心爱的男友。在机场,慧媛与从国外回来的敏宇擦肩而过,感受到了心脏的快速跳动。回国后的敏宇去往了当年曾和未婚妻一起爬过的山,在那与迷路的慧媛相遇。二人被困在山上,有了交流。慧媛再次感受到心脏的快速跳动,而敏宇在慧媛身上看到了逝去的未婚妻的影子。为了感谢给自己捐赠心脏的一家人,慧媛寻着线索奔波,而在目的地她遇到了探望未婚妻家人的敏宇,原来二人被这样联系着……。