300-nen Fuuin Sareshi Jaryuu-chan to Tomodachi ni Narimashita

Performing a summoning spell calls a monster and binds them to the summoner's command in exchange for fulfilling their desire. Youta is a young man who lives alone and decides to try a simple spell—just so he can talk to someone. But having been told that he does not possess any talent for summoning, he has low expectations.

To his surprise, Youta ends up summoning Mumu, a dragon who had been sealed away in the dark for 300 years! Initially, she makes Youta fear for his life. After conversing with Mumu, however, he discovers that her only wish is to have someone to talk with—just like him! They quickly become friends, but Mumu turns out to be an incredibly emotional and needy dragon. Now faced with her endless daily antics, Youta searches for a way to properly handle his new quirky dragon companion.