After enduring severe bullying, Daichi Katsuragi and his classmates are suddenly transported to another world. Despite his efforts to become a hero, Daichi finds himself abandoned in a Monster House due to his perceived uselessness. Facing certain death, Daichi miraculously survives and awakens with a newfound power called 'Revenge of the Grudgebearer.' This unique ability grants him immortality and unparalleled growth each time he perishes. Armed with this formidable skill, Daichi embarks on a quest for vengeance against those who wronged him.