Kyung-hee's neighbor, Soo-jung, is in a fierce custody battle with her ex-husband, Bo-sung. As the opposing lawyer's petty pressure intensifies, she turns to a private investigator for the first time.

Kyung Hee and Jae Hong receive a mysterious blackmail message demanding a massive sum of money. They scramble to find the cash within the time limit, but things quickly spiral out of their control.