The Tatami Galaxy follows a lonely third-year college student who looks back on the two years he has already wasted at university after a chance encounter with a man with an eggplant-shaped head and a self-proclaimed god of matrimony. One autumn evening at a mysterious ramen stand behind the Shimogamo Shrine, he replays the time he spent with his only friend Ozu, a ghoulish-looking troublemaker who seems determined to make his life miserable by dragging him into schemes to break up couples on campus. Each memory sharpens his regret and his hope that he can still make something worthwhile of college life.
When he tries to ask out Akashi, an unsociable but kind-hearted underclassman, and fails at the crucial moment, he is hurled back to the beginning of his university years. From there, The Tatami Galaxy turns that impossible reset into a surreal, energetic story about choices, regret, and the elusive rose-colored campus life he always imagined. Again and again, he tries to choose differently, chasing friendship, love, and a path that does not end in the same dead ends, while the world around him keeps testing how much a single decision can change the shape of a life.