Sang-hyun (Song Kang-ho) runs a laundry shop, but unfortunately the business is slow and he is heavily in debt. His good brother Dong-soo (Kang Dong-won) is an orphan himself and works for a "baby storage box" agency. On a rainy night, they secretly took away a baby boy in one of the boxes. The next day, the young mother So-young (Lee Ji-eun) came to ask to take back her child Woo-sung! She wanted to call the police, but So-young finally agreed to let two "middlemen" find better parents for her son and decided to follow them. On the other hand, detective Soo-jin (Bae Doona) and her junior Detective Lee (Lee Joo-young) have been following them, secretly collecting evidence and determined to pull people to make a case! The plot is triggered by the baby in the temporary storage box, involving 5 key people around, and embarking on an unexpected and unique journey, touching the most subtle worldly feelings.