Mari has always been in love with her older brother Tsuyoshi, who excelled in both studies and sports. But now he's failed and is a NEET. One day, Tsuyoshi, who has been holed up in his room, makes a suggestion to Mari. "Let's play King's Game!" Mari, who cares deeply for her brother, decides to play King's Game with Tsuyoshi. Then, as King, Tsuyoshi issues a shocking order... "From today for two days, I'll be your King all the time, so you must obey all my orders!!"