除夕，雪夜，滨海城市通海。夜幕降临，灯火通明，整个城市充满了节日的喜庆气氛。一声巨响，一辆吊车撞断了高压输电线路，突如其来的事故使城市陷入了黑暗，一张张清晰的面孔在昏暗的应急灯下变得模糊和惊恐不安。医院里，手术灯下正在进行手术的危重病人虚脱的身体，医生额头的汗珠，颤抖的 手术刀，随着灯光慢慢地黑下去……

楚峥岩（陈龙 饰）、崔希（张雅琳 饰）、夏文心（马伊琍 饰）和肖煜路（保剑锋 饰）是同班同学，身为班长的楚峥岩个性正直善良，品学兼优，然而，楚峥岩出生在一个并不富裕的家庭之中，尽管被理想中的大学录取，但坚强的他还是选择了放弃学业，外出工作以资助家庭。
楚峥岩和“班花”崔希互有好感，然而，崔希出生于外交官世家，两人家世相去甚远，身份地位悬殊巨大，楚峥岩因此而产生了退却之情，企图放弃，可是，善良独立的崔希却一再坚持。与此同时，家境富裕的肖煜路亦暗恋着崔希，而在楚峥岩背后一直默默注视着他的，是平凡但努力的夏文心。

The tense hours on board a stricken passenger aircraft that was on a routine flight from Shanghai to Beijing. Shortly after taking off, the pilot Li Jiatang discovers that the plane's landing gear is unable to be retracted. Unable to continue, but unable to land, he and his flight attendant wife Qiu Xiehua, are forced to circle Shanghai. Meanwhile, on the ground, a troubleshooter Liu Yuan is called to see if he can get the aircraft safely back on the ground.