Ontama!

Ontama! (おんたま!) is a Japanese manga series written by Noboru Maeda which was serialized by "Comic Yoshimoto". The anime adaptation streamed for 5 episodes from August 2009.

Plot
Ichigo is a little girl who is distressed by the failing relationship between her mother and step-father. After school one day she meets a driver of a magical bus and finds herself taking a ride in the bus. The bus transports her to the past to shortly after her mother and real father met. Perhaps she is meant to do something that will help her parents stay together and love one another further into the future.