Chokotto Sister

When Haruma Kawagoe was a boy his mother had a miscarriage; and to make up for it, Haruma asked Santa for a little sister at Christmas. Now, years later, Haruma is a college student living away from home. His slumber is disturbed one night by the faint sound of… Santa on a flying motorcycle?! She has come to deliver a present that has taken many years to make: a little sister of his own, a little girl he names Choco. The two of them begin to live together but Choco has a lot to learn, and all of her life skills must come from what her brother tells her and her instruction manual. Choco's life is her brother, but as time goes by she gradually learns to become her own person.