A Letter to Momo

A Letter to Momo (ももへの手紙, Momo e no Tegami) is a 2011 Japanese anime drama film produced by Production I.G and distributed by Kadokawa Pictures.

Plot
After her father's death, 11-year-old Momo Miyaura leaves Tokyo with her mother and moves to an old remote island in Seto Inland Sea. The only memento left from him is an unfinished letter with only two words inside: "Dear Momo"—along with her heart's unrest from it.

While Momo reluctantly tries to adjust to the quiet surroundings and exploring the attic of her new home, she finds a worn out picture book about youkai. Following this discovery, strange things begin to happen around town, and Momo is greeted by the arrival of three troublesome youkai.