A recently discharged soldier is cheerfully making his way along the path. He encounters two young bears. Desperately, they beg for his help, as their grandfather has fallen into a trap. The soldier manages to free the old bear. Full of gratitude, the bear warns him about the enchanted forest and its eerie inhabitants. A gruesome monster is said to lurk there. Despite all warnings, the soldier continues on his way and meets little Vanya, whose mother, Marie, has been kidnapped by the water spirit. The soldier wants to help the boy. Immediately, they both set out to search for her. Then a giant appears before them, the ruler of all moors, swamps, and waterways. The soldier and Vanya have found the dreaded water spirit and want to know where he is holding Marie captive. He invites them into his underwater palace, and Vanya is put to a difficult test.