Misa Kasuga is a 34-year-old single female office worker. As she watches the younger staff at her company quit left and right to get married, Misa discovers that her boyfriend has been cheating on her, and their relationship comes to an abrupt end. Approaching her 40s, Misa worries about being labeled as "unwanted leftovers" at the company, but she is then invited out for a drink with her handsome boss, Noguchi. Getting drunk, she ends up impulsively proposing to him, but this unexpectedly results in the two becoming close! However, there are rumors floating around that there is some reason behind why the 40 year-old Noguchi is still single...!