Kyung-hee's neighbour, 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.

As the two families become neighbours, their teenage daughters quickly grow close. But when trouble arises with the kids, Kyung-hee and Jae-hong must make a tough choice as parents.

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.

Kyung-hee, Jae-hong, and Soo-jung face off in a three-way confrontation, each fuelled by their own misunderstandings. The children worry it's because of them, but this is strictly adult business.

Kyung-hee walks out of the house, leaving everyone in a state of chaos. Meanwhile, Ye-ji and Min-seo are left in shock after stumbling upon the adults' secrets.

Kyung-hee, Jae-hong, Soo-jung, and even Bo-sung gather at Kyung-hee’s house, turning it into an absolute madhouse. But the arrival of an uninvited guest sends the chaos in a bizarre new direction.

Ye-ji and Min-seo find themselves in grave danger. To save their children, the parents must temporarily set aside their bitter grudges and join forces.