Cheat On Me, If You Can - Season 1 Episode 6

Although the police have Yeo Joo as a suspect, she plays it cool and believes that they can't pin anything on her without a motive. However, little does she know, the police have Woo Sung on camera entering Baek Soo Jung's studio apartment. Later, Woo Sung decides to tell Yeo Joo about his affair with Soo Jung, and his blackmailer collapses when he realizes he doesn't have the footage of Woo Sung anymore.