Hidomi Hibajiri is a disillusioned young girl who never removes her headphones. Her entire life consists of attending school, helping out at her mother's cafe, and listening to music. With nothing else to break the crippling monotony, she keeps her headphones on at all times. That is, until she is run over by a mysterious woman wielding a guitar. That same night, a robot barges into Hidomi’s room along with Ko Ide, a boy from her class, and the two are chased around town together. They are saved by the guitar-wielding woman from before, but now Hidomi has a horn growing from her forehead? Who knows where these robots are coming from, what kind of vespa woman this weird guitar woman is warning her about, or what this thing on her forehead is, but it doesn't look like Hidomi is going to be able to ignore all this with headphones!