Kobato decides to become an honest, humble citizen after enduring a bitter experience known as “wisdom work.” He forms a pact with Osanai, his classmate with the same goal, and they plan to enter high school leading quiet lives. But for some reason, inexplicable events and disasters keep happening around them. Will Kobato and Osanai ever manage to live ordinary, peaceful lives?

Hikaru’s ordinary middle school life takes a thrilling turn when he encounters Alma, an alien entity resembling a mechanized limb called Mecha-Ude. Alma, a member of a rare species, is fleeing from a sinister group hunting their kind down in search of one possessing unparalleled power. Tasked by the resistance group ARMS, this unlikely duo will embark on a perilous journey to save the Mecha-Ude.