Calypso Lillis is a siren with a very big problem that wraps around her arm and starts in the distant past. Seven years ago, she put together a bracelet of black beads, magical receipts for the services she asked to provide. And the beads will disappear only after death or repayment of the debt. Everyone knows that if you need a service, feel free to contact the Merchant, and he will provide it. He can get anything... for a price. And everyone knows that sooner or later he will demand payment of the debt. But the Merchant never asked one of the clients to pay. Until this moment. When Callie finds the fairy Night King in her room, standing with a smile on his lips and a mischievous sparkle in his eyes, she realizes that everything will soon change. To begin with, one chaste kiss - the price of one bead - and then the promise of something much more. For the Merchant, this is not just a matter of rekindled feelings, but something more important. Something is happening in the Otherworld. The fairy warriors disappear one by one. Only the women return, each lying in a glass coffin and clutching a child to her chest. There are also rumors among the servants about awakened evil. If the Merchant has any hope of saving his people, then he will need the help of the siren, whom he once abandoned. But his enemy has a passion for exotic creatures, and Callie turns out to be one of them.