The Tatami Galaxy is a story about a third year university student in Kyoto, Japan who feels like he's wasted his first two years of University on his current student club. He hasn't found a girlfriend and has only made two friends: Ozu, who he deems to not have a single redeeming quality as a human being, and Ms. Akashi, a stoic first-year engineering student.
One night, the protagonist encounters a deity of matrimony during dinner. The deity tells him that Ms. Akashi will end up paired with either him or Ozu, and it's up to him to take the opportunity that is dangling in front of him or not.