Escape Attempt

Escape Attempt is a 1962 science fiction novel by Soviet writers Boris and Arkady Strugatsky, set in the Noon Universe. The English translation was published in a single volume with the other Noon universe stories Space Mowgli and The Kid from Hell.

Plot summary

The novel tells a story of two young men from Earth, Anton and Vadim, who decide to go for a trip to Pandora, but are persuaded rather to travel to an uncharted planet by a mysterious man whom they know Saul Repnin. Their choice is an unnamed planet in EN-7031 system, because that's where Gorbovsky and Bader predicted that Wanderers' traces could be found.
After landing successfully on the planet, the explorers soon discover a local human civilization, as well as the predicted Wanderers' traces. The latter appear as a phenomenon later called "everlasting machines" and largely influence the entire local population. Despite the fact that it is strictly forbidden for them to initiate a contact with any human or alien civilization without an authorization from COMCON, they try to do just this - and fail, having misinterpreted the situation. What Anton and Vadim see as catastrophic is just a routine life in an early feudalistic society of Saula.
Saul Repnin, who, as it was later uncovered, was from 20th-century Earth but shifted into the future, is so shocked to see a local civilization commit just the same cruelties he saw in his time, that it causes a severe psychological crisis in him. Anton and Vadim decide that it's the best to leave the planet immediately. On arriving back to Earth, they discover that Saul has disappeared, leaving a short note, which partly explains who he was and that he wants to go back to continue his fight against the Nazis.
Saul Repnin was killed in a firefight soon after he returned to his time.