Going to another world seems fun and all... until you experience it for yourself. Tsukasa Ryo, a usual first year high school student, was caught up in a summon inside his classroom; that is, until an error occurred. He became the fifteen-year-old scavenger, Rein, who is on the verge of death. What's more, the world he went into is far more technologically advanced than the place he came from. The people in that world aren't as gullible as most fictitious works show, either. "This isn't the standard package, isn't it..?" It seems like this is truly an unusual isekai story.