Shinonome Neo, 28 years-old and single. During his school life, he was often teased by his senpai, Maki Yuuki. That is how, even twelve years later, he can't trust in other people or even have a girlfriend.
When he receives the invitation to the wedding of Maki, he decides to take revenge and spoil it...but destiny is cruel with Neo and he dies. After this, his spirit travels back in time, which gives him the opportunity to change everything and avoid the misfortune in his entire life.
(Source: MU, edited)