Ikurou Hoshi and Sara Haizaki serve as concierges at Hotel Inhumans, a facility that specifically caters to assassins. They fulfill every request their guests may make, never uttering the word "no." While Ikurou specializes in researching his clients' backgrounds and careers, Sara protects the hotel with skills that match those of its patrons. However, despite providing every imaginable service for these assassins, Ikurou despises those who kill for money and claims daily that he is going to quit his job. Yet, the more requests he and Sara fulfill on behalf of their guests, the more Ikurou learns about the unexpected humanity found within the assassins. With every glimpse into the lives and motivations of those who murder for a living, he realizes more and more that assassins are not so different from him or Sara.