Kuroe Akaishi keeps to herself in high school, partly out of shyness and partly because of a rare condition that turns her into a hulking kaiju whenever her emotions run too high. Her carefully managed distance from everyone starts slipping the moment popular classmate Arata Minami keeps making her heart race despite her best efforts to avoid him. As her feelings for Arata intensify, so does the risk of her monstrous side breaking through, and Kuroe has to decide whether he can ever handle who she really is.