突然有一天之2月29日

美丽的少女韩智妍（朴恩惠 饰）曾是一名高速公路的收费员，如今她身在五井精神病院，罹患严重的失眠症，精神恍惚，憔悴不堪。一名记者（任浩 饰）听说了她的离奇经历，于是专程来此，智妍也向他讲述了一段匪夷所思的故事：数年前，智妍还是一名自信乐观的女孩。在2月29日的午夜，收费站的灯光突然全部熄灭，与此同时，一辆黑色汽车向智妍的窗口驶来。她竟收到一张血迹斑斑的票。次日，智妍从广播中听到附近收费站人员被人乱到杀死的新闻。原来，12年前高速公路上发生一起严重车祸。从那之后，每隔4年的2月29日，高速附近就会发生杀人惨案。从那天起，智妍仿佛总会看到12年前的亡灵，她的生活变得一团糟。 　　而，真相究竟如何？Ji-yeon, a tollgate ticket girl, is frightened by a mysterious black car, which hands over a bloodstained ticket as a fee at midnight. Her fear deepens after her colleague, Jong-sook, tells her that 12 years earlier a prisoner transport vehicle caused a traffic accident wherein all the prisoners involved died - and some of the corpses disappeared. Since then, a murder has occurred near the tollgate on February 29th, every four years. Soon, odd events become increasingly frequent, usually involving a doppelganger of Ji-yeon. When Jong-sook is killed on the fateful February 29th, Ji-yeon - with the help of two detectives - starts looking into matters herself.