讲述公安边防战士“兵王”史建国，在抓捕越境毒枭，营救著名化学专家时，中枪落水失忆，流落他国，被当地贫民小女孩阿水救起，成为一名普通的渔民。可是，碎片般的记忆里，一名中枪的小女孩却成为他摆脱不了的“梦魇”。在找寻记忆的过程中，他发现自己的出现竟给阿水一家带来了灭顶之灾，阿水被当地最大贩毒集团绑架，史建国毅然重新拿起狙击枪，与贩毒集团决一死战…
Gyeong-ah works as a caregiver and lives alone. The only one she can rely on is her daughter, Yeon-su, but it's hard to see her after she moved out on her own. Meanwhile, Yeon-su, who is suffering from her ex-boyfriend, Sang-hyun, argues with him again and visits her mother’s house. After Yeon-su left, Gyeong-ah receives a shocking message from a stranger.
