Luna Winchester can search for precious stones and metals. The magic was passed on to her from the witch mother, and she hears them singing. Even if they are difficult to find. She is the best thief in the city. And when the gang pins her against the wall and tells her to steal the Crestfall Diamond or die, she decides to steal the diamond. But there is a problem.

Monster. They say the aristocrat who protects the diamond is the worst. Not a real monster, of course, but he caught all the thieves. So Luna needs to be more careful, more cunning than before. The challenge is nice. She always liked those who underestimated her. But it's not that simple.

The Diamond is calling her, yes, but the monster is cunning. He catches her on the first night and offers her a different deal. Work for him, turn in the gang members, and he'll let her live. Luna wants to live, so she lies through her teeth.

But the nights are long, and the real monster is hiding in the aristocrat's house. A beast with fur, claws and familiar eyes. With eyes that she begins to fall in love with.