The story takes place between the first and second seasons, where Rimuru confronts the swirling conspiracies in the Coleus kingdom.

In 2138, the last player of the online game Yggdrasil somehow stays logged in after its shutdown. Now he's on a quest to learn what happened and why.

Two brothers witness a UFO, sparking their dream of space travel. Years later, the younger brother pursues being an astronaut while the older regains his drive and applies to the space agency, hoping to fulfill their childhood promise.