Overworked salaryman Arihito Atobe dies in a bus accident and wakes in Labyrinth Country, where newcomers pick a job class and register with the Seekers Guild to explore its labyrinths. When Arihito chooses Rearguard, the class name turns into an ancient script no one at the guild can read. It proves to be a support class that works from behind the party, boosting allies' attacks and shielding them. His first companions include his former boss Kyoka Igarashi, now a Valkyrie, and Theresia, a lizardwoman rogue.