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.