Koroshiya to Strawberry

In a city somewhere in modern day Japan the protagonist 'Ichigo' is drugged, put in a case and taken to a certain place. When she wakes up she is somewhere normal people can't enter, 'Cafe Tsukikage', a cafe where people who deal in illegal business gather. Because it exists in the underworld even the owner and waiter at the cafe are contract killers. While Ichigo is wary, the owner of the cafe Tsukimi explains that he has accepted a certain request. "This request isn't a kill contract, it's t