Seong Jae works at a major firm, but always works late due to the workload. Once, he falls asleep while working overtime and reaches the Sleep Bank, where he takes a sleep loan from the branch manager. Seong Jae returns to the sleep bank after continuous nights of overtime and extends his sleep loan. Seong Jae manages to reach his target achievement thanks to the sleep loan, but the interest has built up, and the time when he has to pay it all back has come.