Caught in a vicious cycle of oppression, Chinese immigrant Jin Xia (Fan Bingbing) works at customs at South Korea’s Incheon airport. There, she encounters a mysterious green-haired girl (Lee Joo-young) who behaves suspiciously at the security checkpoint. Overwhelmed by the unspoken attraction between them, she takes the mysterious stranger home, only to discover that she is involved in a deadly drug ring.