The story “The Leap at the Mouth of Lethe” can be called a “spin-off” to the work of Arkady and Boris Strugatsky “The Beetle in the Anthill”. The action takes place a couple of decades later, when Lev Abalkin visited the planet “Nadezhda” in the company of Golovan. What happened to Nadezhda then? Were the “foundlings of the Wanderers” the only creatures raised by earthly civilization? Where did the Wanderers take the aborigines from Nadezhda and why did they kidnap the children? The answers to these questions can be found inside.