An American expedition of five people, returning south from the Canadian north, came across strange traces, the origin of which forced scientists to build a number of assumptions. And, to their general horror, it soon became clear that the most terrible of theories turned out to be true - about the existence of a powerful extraterrestrial civilization conducting experiments on people.

This story was included in the “First volume of the anthology of the best horror stories of the 20th century” (1901-1950)" - "Century's Best Horror Fiction. Volume One", 2012.

Illustration for the story: Frank R. Paul.