1979, the heyday of the USSR, the following year - the Moscow Olympics. And in the city of S. an epidemic of an unknown disease begins, which could destroy the city’s population, change the leadership of the special services and cancel the Olympics. Against the backdrop of a monstrous threat, emergency doctor Sergeev is investigating a seemingly inconspicuous murder. What will it lead to? Sergei Leontiev began writing the novel “Ulcer” long before the coronavirus pandemic, but suddenly the events of 40 years ago became extremely relevant.