30-year-old office lady Minako bolts from work every day at exactly 5 o'clock to rush over to the local dart bar, simply to be near her crush Shinozuka. One night she plays darts against an expert and gets soundly thrashed and embarrassed in the match. Knowing that Shinozuka has aspirations of going pro, Minako makes the bold prediction that she's going to win the national soft-tip dart competition. However, in order to beat her rival it's going to take a lot of practice in a relatively short amount of time.