Tazuna ist ein Junge, der ein Talent dafür hat, Dinge zu reparieren. Doch als er eines Tages ein komatöses Mädchen findet und dieses berührt, krempelt sich sein Leben um. Denn plötzlich findet er sich in einer Welt des Kampfes …
High school student Tazuna Takatsuki is a kind young fellow who is in love with mechanics, stopping anytime to help anyone fix anything problems that have to do with mechanics, and he is almost always successful. When he goes to an university to meet a scientist named Nagamasa Makihara who has requested his help in fixing something, only to come across a hospital room where a young girl with short white hair is lying unconscious on a bed. Reminded strongly of his deceased sister, Tazuna approaches the girl, only for her to wake up and reach for his hand. The moment their hands make contact, both of them are transported to an alternate reailty, where Tazuna collapses, only to wake up to find himself back in the room, with the girl awake and Makihara dancing with glee. Makihara barely explains the details clearly, only bluntly stating that Tazuna cannot let go of the girl, Koyori Akutagawa's hand or else she will die. When Tazuna looks up however, Makihara is gone, and the duo are attacked by metal chains snaking through the walls. The two escape, only to be confronted by a rebellious-looking man that controls the chains, along with a young woman treated like a puppy dog. The man roughly introduces himself as Break and the girl Bind, but makes one point clear: he has come to kill them. Tazuna and Koyori runs, but the chains are everywhere. It seems the two are doomed, when metallic gears materialize suddenly, forming a protective barrier around Koyori and Tazuna before taking the form of a sword. Together, Tazuna and Koyori stab Break as Bind reaches her limit, and wins the battle.
Tazuna est un lycéen lambda qui ne demande qu’une chose : bricoler des machines tranquillement. Sa rencontre avec Koyori va cependant bouleverser sa vie et l’entraîner dans un combat à mort entre élus, les Hand Shakers.
機械いじりが得意な高校生・高槻手綱（タヅナ）は、修理依頼に駆け回る日々を送っていた。
ある日、大学部の准教授・槇原長政（マキハラ）からの依頼で、彼の研究室へと訪れる。
そこにはベッドで眠り続ける一人の少女が。
何かに導かれるように彼女の指先に触れたタヅナに、どこからか声が降り注ぎ——。
Tazuna è un giovane che ama riparare le cose. Ma la sua vita prende una piega inaspettata quando incontra una ragazza che giace in un letto d'ospedale all'interno di un laboratorio dalla porta con chiusura elettronica. Quando la prende per mano, capisce di non poterla mai lasciare, o lei morirà.
