While all of Japan focuses on the possible record-breaking baseball play in the stadium, underneath the wild tension, another game is at play. A mysterious murder takes place and the director of the Natsugawara Stadium, the executive Ryuusei Takioka and the senator Ranzou Hiura try to hide this mystery before the mass media ruins their elite status. Unfortunately for them, a certain infamous informant in a wheelchair happens to be at the game, and the hidden murder mystery becomes more deadly for all those involved.

This is a four-part Durarara!! series made for Niconico and the 10th anniversary of Durarara!! and 20th anniversary of Dengeki Bunko. They take place after Vol. 13's events. There are spoilers for the end of the novels. This series also serves as a prequel to Durarara!!SH.