Our protagonist, wishing to return to the old days, goes back in time to get revenge on the girls who bullied him as a kid. His big sister Saki... and his classmates are definite candidates.... But how about his childhood friend, Sera...?
Watch Gaki ni Modotte Yarinaoshi!!! (Making A Cumback to Early Days!↹ガキにもどって犯りなおしっ!!!) on oppai.stream for free!