"If you want to get a lot of gifts for your birthday and read a lot of compliments, take care of it yourself, otherwise everyone will forget." So said Evlampia Romanova, her friend Anechka and asked her to help organize a surprise for the birthday of her mother-in-law, whom everyone calls Murlysya. The gift was a success: a luxurious chocolate puzzle in the form of a Palace and its inhabitants. Quickly collecting all this splendor, the women sat down to drink tea. Lampuse and Marlyse it became a pity to have such a beauty, but Anya had a good feast from the heart and... got to the hospital! Evlampia and Max turned to Professor Moses Silbercrantz, a well-known expert on toxic substances. He came to the conclusion that Anya was poisoned with the poison of the Cone snail found in the chocolate present. But his colleague Yuri Derevyankin insisted that Zilberkant was wrong. This poison is obtained from the lizard toothpick. And soon Moses Abramovich takes his own life. Why?! Proud Monya did not survive the shame? It's not like him. Wolfe and his team begin an investigation, unaware of how many more deaths are waiting for them outside the gates of the chocolate castle!