Ema suffers from memory loss. One day she gets a drawing of an elephant from Yang , a childhood friend who has gone missing. With the postmark as her only clue, Ema heads on a journey to find Yang with her childhood friend Ban and his girlfriend Yuri .

A seemingly unremarkable man called “Mouse” is caught by the police. In exchange for his freedom, he goes undercover, infiltrates a drug ring, and arranges a fake deal, but an unexpected turn of events occurs.