My Big Sister Arrived - S01

Tomoya Mizuhara is a 13-year-old boy whose life takes an unexpected turn when his father remarries, giving him a new stepsister: 17-year-old Ichika. She’s a bit odd, and her intense affection for Tomoya borders on unsettling. To make matters more complicated, Ichika’s friend Ruri has a cruel, sadistic streak, while her other friend Marina-who is part Japanese-is notably busty.