Tanaka-kun's Summer.Tanaka suggests visiting a pool, despite not knowing how to swim and must use an inflatable. Two boys burst his inflatable, causing Ohta to realise Tanaka’s listlessness makes him float without effort. The WcDonalds waitress, who is also a lifeguard, is too nervous to say anything. The next day they meet the boys again who reveals listless floating has become a fad at their junior school...