《记忆之夜》是一部讲述兄弟故事的惊悚片，哥哥因绑架事件失去了记忆，弟弟则一直在为哥哥找寻记忆 。Jin-Seok (Kang Ha-Neul) moves into a new home with his older brother Yoo-Seok (Kim Moo-Yul), mother (Na Young-Hee) and father (Moon Sung-Geun). Jin-Seok suffers from hypersensitivity, but with medication he is able to live normally. One rainy evening, Jin-Seok sees his older brother being thrown into a van by a group of men. After 19 days of silence, Yoo-Seok returns home, but he doesn't remember anything from his disappearance. Jin-Seok though notices enough changes in his older brother's personality and behavior that he begins to suspect that the person who has returned is not Yoo-Seok. Meanwhile, Jin-Seok keeps hearing sounds from a locked room temporarily storing the previous home owner's belongings.