Student teacher Kang Eun-kyung encounters a group of girls in a black magic club who are topping the national mock exams.

The three women are curious about the situation in room 404.

"I just got dumped. Will you have breakfast with me?" At a breakfast club, heartbroken Sa-gang and Ji-hoon stumble upon mysterious "breakup souvenirs." Each item holds a secret pain, reflecting their own. Will they find the souvenir's owner?