A sentient robotic arm living in your hoodie sounds absurd until you realize the show actually commits to it. The chemistry between Hero and Mecha-ude has the warmth of a buddy cop movie crammed into an OVA that refuses to waste a single frame on exposition. You get the action, the weird-as-hell premise played straight, and a kid learning that the strongest partnership isn't about power, it's about someone choosing to stay with you even when they could leave.
Hero's ordinary high school routine shatters when a sentient mechanical arm drops into his life with zero warning. The arm, calling itself Mecha-ude, is intelligent, powerful, and immediately decides that Hero's hoodie pocket is the perfect home. What starts as an awkward cohabitation becomes something deeper when they're forced to fight together against threats neither fully understands. Hero soon discovers he's not alone. Other students carry their own Mecha-ude partners, each with different abilities and personalities. Among them is Akagi, a bold and spirited girl whose confidence stands in stark contrast to Hero's hesitation. She operates with two Mecha-ude at once, and Hero finds himself drawn to her determination even as the complexity between them grows. But harmony doesn't last. Mysterious forces hunt these mechanical weapons, seeking answers about their origins and power. As Hero and his growing circle of allies clash with relentless pursuers, they must figure out whether their Mecha-ude partners are tools to be wielded or something far more significant. The bond they share might be the only thing that saves them.