Locked, Observed, Revealed…

‘Su-yeon’ (Cho Yeo-jeong), a cellist in an orchestra led by her fiancé and conductor ‘Sung-jin’ (Song Seung-heon), disappears one day, leaving behind only a video recording. Sung-jin is devasted over the loss of Su-yeon, but feels a strong attraction to ‘Mi-ju’ (Park Ji-hyun), a cellist who fills in for his fiancée. Then one rainy night, Sung-jin and Mi-ju get swept away by their mutual desires for each other and commit an unforgivable act at Su-yeon’s house.

Meanwhile, Su-yeon, who is thought to have gone missing, remains trapped in a secret room inside her house, and watches the naked truth unravel before her.