Opening by chance done by a professor by Mikhail by Vladimirovich Свешниковым in 1916 influences on a fate each, who adjoined with him, tightens in the whirlpool of political love affairs and ancient myths, gives a chance to change motion of history, puts before an impossible choice.In the third book of novel "Source of happiness" Mikhail Vladimirovich Свешников and Fedor Агапкин are court doctors of red leaders. Before them secret mechanics is opened out events of 1921-1924 gs Their patients is Lenin and Stalin. Leaders amuse itself a hope to get medicine from old age and death.The past interlaces with a present, reality appears a chimera, ancient myths - by reality. A multimillionaire Peter Borisovich Кольт is ready on everything, only to extract the cherished preparation. Biologist Соня Лукьянова must unriddle secret of opening of the прапрадеда. An aim is near, solution is almost found. Remains only to glance in eyes to the abyss.