In a desolate, sand-covered planet, stands the lonely sauna facility "Galactic Health Center." With its dried-up sauna and empty cold baths, customers rarely visit. The mascot, "Toto," spends her days bored, literally just polishing the signboard. One day, a spaceship carrying a massive amount of water crash-lands nearby. And thus begins a grand "stellar revitalization" project spanning three light-years, all in search of "Totoi" (refreshment and rejuvenation).