The novel describes the "Ark Project" of 2160 and the first (and last) contact with Ark Megaforms. The story is told by Stanislav Popov, a technician of the ER-2 team, one of the twelve ecologist teams that were working on Ark to prepare the planet for the arrival of the colonists from Pant. The ER-2 consists of Popov, Gennady Komov, Maya Glumova and Yakov Vanderhuze.

The story begins as the members of ER-2 go on a routine exploration mission while Popov is left behind to oversee the construction of a permanent base for the arriving colonists. Suddenly, the construction robots get out of control and leave the construction site. It takes a few hours for Popov to locate the robots, fix them and set them back to work.

After that, Popov hears a human baby crying. Popov tries to locate the source of the sound but the crying stops as suddenly as it started. Since infants are not allowed to leave Earth, Popov assumes he had an auditory hallucination. Popov carries on his work with the robots. Now, he hears a female voice pleading for help from somebody named Shura. Popov cannot locate the source of the voice either...

Meanwhile, the ER-2 exploration party discovers the wreckage of an Earth spaceship and the remains of its two pilots. They log a report describing their discovery with the orbital base. The following night, the ER-2 members start to exhibit the symptoms of psychosis. Popov is the most heavily affected. However, he does not tell the others about his condition: if he is found to be unfit for duty he might be recalled to Earth.