A woman is attacked by Internet users after posting provocative remarks online. Using her personal information, they go to her place but what they find is her body; she took her own life. Who made her kill herself? Or, was she killed by someone else?

Yeo-jin and Jae-yeong are two teenage girls who are trying to earn money for a trip to Europe. To reach this end, Jae-yeong is prostituting herself while Yeo-jin acts as her pimp, setting her up with the clients and staying on guard for the police. Things take a turn for the worse when Yeo-jin gets distracted from her duty and the police raid the motel where Jae-yeong is meeting with a client. To avoid getting caught, Jae-yeong jumps out of a window, fatally injuring herself.

Ji-yeon, a tollgate ticket girl, is frightened by a mysterious black car, which pays a bloodstained ticket 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. Afterwards, a murder 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.