Maria Semenova's cycle about the Wolfhound has long become a classic of Slavic fantasy. The book “The Source-Stone” describes the adventures of the last warrior from the Gray Dog clan before the events that occurred in the novel “Wolfhound.” Captivity. Slavery. Underground mines. Hard labor is terrible, but even more terrible when a former friend turns into a bitter enemy, and those to whom the soul is drawn, one after another go into oblivion... In order to win freedom and preserve the person in himself, a boy named Puppy becomes a Wolfhound...