In WW2, twelve year old Soviet orphan Ivan Bondarev works for the Soviet army as a scout behind the German lines and strikes a friendship with three sympathetic Soviet officers.
A psychologist is sent to a space station orbiting a planet called Solaris to investigate the death of a doctor and the mental problems of cosmonauts on the station. He soon discovers that the water on the planet is a type of brain which brings out repressed memories and obsessions.