Soviet Scientist Petrovich pioneers the way to the Sun, but his spacecraft is never heard from again. Later, Andrew's laboratory investigates means of protection from deadly radiation. Andrew repeats Petrovich's journey, and offers his life to rescue an orbiting science laboratory, which holds the solution to the problem.

The picture is dedicated to the work of Soviet medical scientists who studied how stresses that are unknown under ordinary earthly conditions affect a living organism: overloads during exit from the atmosphere, a state of weightlessness, oxygen starvation. Experiments were first carried out on animals: dogs and rats, and later people also participated in the experiments.