After falling down the stairs at his cram school and suffering serious injuries, Shinji is left bedridden and alone at home while his parents are away on a trip. Worried about him, his older brother Kazuo and sister-in-law Tamaki come to visit. Shinji has secretly been in love with Tamaki for some time, but his current physical and mental state has pushed him to the brink. Sensing his distress, Tamaki approaches him with gentle yet mischievous affection. She makes him promise to "just watch," then proceeds to act on that promise in unexpectedly bold ways, teasing and seducing him directly. Her actions become the catalyst that further destabilizes Shinji's emotions.