Otkrytie, sluchaino sdelannoe professorom Mikhailom Vladimirovichem Sveshnikovym v 1916 godu, vliiaet na sudbu kazhdogo, kto s nim soprikosnulsia, zatiagivaet v omut politicheskikh intrig i drevnikh mifov, daet shans izmenit khod istorii, stavit pered nevozmozhnym vyborom. V tretei knige romana "Istochnik schastia" Mikhail Vladimirovich Sveshnikov i Fedor Agapkin - pridvornye vrachi krasnykh vozhdei. Pered nimi razvorachivaetsia tainaia mekhanika sobytii 1921-1924 gg. Ikh patcienty - Lenin i Stalin. Vozhdi teshat sebia nadezhdoi poluchit lekarstvo ot starosti i smerti. Proshloe perepletaetsia s nastoiashchim, realnost okazyvaetsia khimeroi, drevnie mify - realnostiu. Milliarder Petr Borisovich Kolt gotov na vse, lish by dobyt zavetnyi preparat. Biolog Sonia Lukianova dolzhna razgadat tainu otkrytiia svoego prapradeda. Tcel blizka, razgadka pochti naidena. Ostaetsia lish zaglianut v glaza bezdne.