Thanks to an intervention from a certain someone, Koutarou and the invaders are now forced to try and work out their territorial dispute peacefully. But when playing cards gets boring, scheming Kiriha and maniacal Theia cook up a plan. Their next battle for control of room 106 will be... the obstacle marathon for clubs at the school sports festival?! But won't the invaders all have to join clubs first? What happens when Koutarou decides there's something more important at stake than room 106? And how does a ghost even run a marathon?