Sekai Meisaku Gekijou Kanketsu Ban: Watashi no Ashinaga Ojisan

Judy is an orphan girl who lives in the United States at the beginning of the 20th century. She has a gift for writing, and is helped by a mysterious benefactor who gives her the opportunity to study at a private high school with only one condition: she has to write him letters every month, with no expectation of them being responded to. However, she knows nothing about this person, not even his name. As she has heard he is very tall, she nicknames him Daddy Long Legs.