Escape Attempt

Escape Attempt (Russian: Попытка к бегству, romanized: Popytka k begstvu) 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.

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 as Saul Repnin. Their choice is an unnamed planet in EN-7031 system, because that's where Leonid Gorbovsky and August-Iogann Bader predicted that Wanderers' traces could be found.

After landing successfully on the planet (which they named Saula after Repnin), 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 (who lived in Anarcho-communism) 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 (a prisoner in a Nazi concentration camp, but originally in drafts he was a Soviet political prisoner) but shifted into the future (s.c. time guest), is so shocked to see a local civilization (even though it's not the Earth's one) 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 (he is armed with a guard's machine-gun).

Saul Repnin was killed in a firefight soon after he returned to his time.

Read more: https://en.wikipedia.org/wiki/Escape_Attempt