An experienced intelligence officer arrives in the USSR as a tourist. The staff of the State Security Committee manages to find out the real reason for Miss Luster's visit, to reveal all her numerous connections with agents of foreign intelligence, to expose and eliminate the criminals.

Group of youngsters find a sunken sailboat used by guerrillas during WWII, raise it, repair it, and sail out to sea for adventure.

1946年，苏联的太空计划正经历着动荡。塞迪克教授正计划领导第一次载人登月探险，他的竞争对手卡林教授谴责他太老，精神太不稳定，无法完成任务。塞迪克教授在助手玛丽娜和一位名叫安德鲁莎的年轻人的帮助下，无视卡林教授的权威，成功登陆月球。尽管月球上出现了一些问题，包括发现了一个损坏的氧气罐和塞迪克教授被困在一块坠落的巨石下，但这次探险是成功的，宇航员们返回了莫斯科。