Watch The Witcher: Nightmare of the Wolf (2021) online

The Witcher: Nightmare of the Wolf is a South Korean-American adult animated dark fantasy film for Netflix, and is produced by Lauren Schmidt Hissrich. The film serves as a spin-off of the Netflix series The Witcher. It focuses on the origin story of Geralt's mentor and fellow witcher Vesemir. The film premiered on August 23, 2021.
The story begins with Vesemir saving a noble child from a leshen in a forest in Kaedwen. Before dying, the creature says something in an archaic elven dialect to Vesemir, leading him to think it was controlled by someone.

Vesemir reminisces about his youth when he, along with his best friend Illyana, were servants for a noble whose mistress had suddenly fallen ill. A witcher named Deglan deduced that the woman was possessed by a Mare and successfully exorcised the monster with Vesemir's help. Enticed by promises of coin and riches, Vesemir left Illyana and traveled to Kaer Morhen, and after years of brutal training and body-altering experiments, he became a successful witcher, notorious for his skills and arrogance.

In the present, Vesemir is visited by the elf Filavandrel, who thinks the leshen was controlled by Kitsu, an elven girl who went missing and was followed by numerous others. He asks the witcher to help him investigate, but Vesemir refuses. Meanwhile, a sorceress, Tetra Gilcrest of the Kaedwen Court, tries to convince the king to wipe out the witchers of Kaer Morhen, but her attempts are unsuccessful due to the efforts of Lady Zerbst, a royal councillor who is sympathetic to the witchers and their cause.