The series' main characters are graduates of the same orphanage. They've been friends since childhood, and their teacher, Lyudmila Petrovna, was like a mother to them. Twenty years have passed. Svetlana decides to gather everyone for a reunion. Lyudmila Petrovna is also invited and has promised to attend. Everyone gathers, waiting for Mama, but she doesn't show up. She doesn't answer her phone. So the boys go to her home. But a strange man is there, saying the pensioner has moved out. Sensing something is wrong, Dima, Shurik, Kostya, and Sveta decide to look for her.
But it's not that simple. No one wants to help them. Getting information is difficult. Dima's charm comes into play. He finds out at the passport office that Lyudmila Petrovna is still registered in her apartment. Sveta visits nursing homes, but Mama isn't there. Shurik recruits homeless people, trying to find out through them where Mama is. They learn that half the apartments in Mama's building belong to some investment company. And there are no families or elderly people left in the building for a long time. Except for one grandfather, Andrei Petrovich, who greets all guests with a gun.
The friends' trail leads them to Father Tikhomir's sect. Shurik recognizes him as a dangerous bandit. But he's serving time. To find out everything, Shurik goes to the sect, telling Tikhomir he wants to find God. He learns that Mama is in one of the locked rooms, like the other old people. They are being forced to sign deeds for their apartments, while being forced to take pills.
Shurik plots an escape. But the plan fails. He himself becomes a hostage to the bandits. Kostya, Sveta, and Dima seek other ways to infiltrate the sect. To do this, they recruit another student, Anya. Lyudmila Petrovna once saved her from rape.
