Watari-Kun No Xx Ga Houkai Sunzen

Story:

Ever since his parents died, Watari Nao's life has revolved around his little sister. He refrains from club activities in order to spend time with her, as a result of which many of his peers think that he is in love with his sister. But while his sister is happy, Nao is ready to turn a blind eye to all this gossip. But Nao is in the same danger as she was with him six years ago. This danger is a girl who will not leave without what she once owned!