Mirai Fukuin (lit. The Future's Gospel) is a side story of Kara no Kyoukai novel series. It is divided into two parts, Möbius ring, and Möbius Link.
Timeline: 1998. Side stories. Adaptation of the manga by Takashi Takeuchi. Premiered and sold with Future Gospel.
The movie follows a 4-year old boy who is struggling to cope with the arrival of a little sister in the family until things turn magical. A mysterious garden in the backyard of the boy's home becomes a gateway allowing the child to travel back in time and encounter his mother as a little girl and his great-grandfather as a young man. These fantasy-filled adventures allow the child to change his perspective and help him become the big brother he was meant to be.
It is summertime, and Shinobu laments not having a boyfriend. She then happens upon a young man weak from hunger, and wearing a rabbit costume. She gives him a carrot, he expresses his gratitude by hitting on her... and she hits back. The young man leaves behind a key to another dimension where everybody's possible futures exist. Lum and Ataru join Shinobu to find the bunny boy, and happy futures for themselves.