From MangaHelpers:
Sukuruma Fuusuke normally works at a government office handling paperwork, but his other job is working at the Uramiya. There are many people that want revenge or payback for what someone has done to themselves, their friends or their loved ones. Some want to ruin the perpetrators financially or socially, while others simply want them dead. This is where the Uramiya (Revenge Shop) steps in. Clients pay to have their revenge while keeping their hands relatively clean and avoiding suspicion from the law. Fuusuke works with a team of skilled agents to complete their missions to make sure that those who deserve it, get what is coming to them.