好高骛远的陈春林（徐彬饰）在殡仪馆工作，意外发现一只可以穿越时空的打火机。他利用打火机投机钻营，回到过去寻找历史名人，再带历史文物回来倒卖牟利。然而，他冒险的行为却不慎改写了历史，还将自己卷入许多名人的命运轨迹。他不得不直面自己的失败，并重新寻找人生的意义。

　　A group of tired commuters have caught the last train home, ready to hop into their beds for the night. However, their train soon veers off-course and crashes into an abandoned tunnel. The three surviving commuters; withdrawn mother Yi Ling, her son Lucas, and student Janice, are forced to band together and survive the night, as well as avoid the mysterious monster hunting them. Yi Ling still suffers from flashbacks to the car accident that killed her husband and nearly took Lucas` life too. When Lucas is snatched away by the monster, her maternal instincts are tested, and Janice`s ideas of family are challenged as she remembers her difficult relationship with her estranged father. Back at the subway control headquarters, the engineers do their best to make sense of the situation and rescue the survivors.