Lendal, autumn 1185. A series of mysterious murders sweeps through the City. Wizards die, young and old, powerful old men and young men, representatives of old families and people who hardly remember their gift. People who do not know each other, who have almost nothing in common with each other. But what is this “almost”? An unknown black four-leaf clover mark is imprinted at the base of the neck of each of the victims. Who are they? Perhaps a Sect? But in five decades it was not possible to find at least some kind of connection between these people. The case, no matter how you look at it, is disastrous, is it any wonder that it was pushed onto the young captain Mel? They say, if you can handle it, well done, but if you don’t, then it’s not a pity. And then this silver-haired little thing, a student of the department of practical use of magic Katherine Rance, stuck her nose into this matter.

Author's notes: This is the first story in a series of stories About Chalk, Katherine And Roset. If "Laboratory Story: Winter Detective". At its core, this is the story of how these three met, and the story of Rosette herself.