Tsurugi Nao works to the bone to support his sick family. However, due to his foolishly honest personality, nothing ever goes his way. One day, while at work, he is stabbed by a malicious customer and loses his life. When he opens his eyes again, he finds himself in an amusement park he has never seen before in his life. Hearing the stories of those around him, he learns that everyone, like him, has experienced death once. Just as he is worrying about his left-behind family, a quest start screen suddenly appears in the sky. It seems that if he clears the quests, he can return alive. However, the condition for clearing is to defeat a boss monster capable of killing a human in an instant...