Secondary school graduates take the Unified State Exam. Graduates of special schools on the Moon, Venus, and Mars also take this exam. Not all of them will be destined to wear a maroon beret with a silver lightning bolt all around. In addition to the Unified State Exam, a cadet at the Center for Training Young Cosmonauts on the Moon still has to undergo certification of space work skills. A cosmic deceiver, in the person of "Cube", on the Earth's satellite will force Petka to risk not only his life, but also the fate of his friends, the life of his beloved. Capturing the carrier of the cosmic infection on the Moon is a new task for the personnel of Petka’s company. The space scammer "Cube" will be able to replace the earth's "training" virus with itself, trying to forever postpone Petka's graduation at the lunar cosmonaut training center. What will win the space race of the mind on the Moon: the artificial intelligence of a giant cruiser-ship in lunar orbit, the artificial intelligence of the Earth's supercomputer, the illusion of the "Cube" deception, or the resourcefulness and intuition of the young cosmonauts of the Center - we have yet to find out.