[3] Wilfred Glendon, a wealthy and world-renowned English botanist, journeys to Tibet in search of the extremely rare plant Mariphasa lumina lupina, which is rumored to be nourished by the moon.

At a party, Wilfred is approached by fellow botanist Dr. Yogami, who claims they met, briefly, in Tibet, where he also was seeking the Mariphasa.

Yogami tells Glendon the plant is a temporary antidote for "werewolfery" (or "lycanthrophobia"), and responds to Wilfred's skepticism by claiming he knows of two men in London who are werewolves, having been bitten by another werewolf.

While Wilfred researches werewolves, learning they must kill someone each night they transform, or they will not turn back, Yogami steals two newly-opened Mariphasa flowers.

Wilfred chooses not to accompany his wife, Lisa, and her childhood sweetheart, Paul Ames, who is back in town for a visit, to her Aunt Ettie's party, and, soon after they leave, he transforms into a werewolf.

Unable to reverse the process, he goes after Lisa, but Ettie's screams scare him away, so he settles for mauling a random woman in the street.

He transforms during the struggle and kills Yogami, and then chases Lisa around the house, knocking Paul unconscious and causing Ettie to faint in the process.

Lugosi would subsequently portray the gypsy werewolf who bites Lon Chaney Jr.'s titular character in The Wolf Man (1941), which was a much smaller, though memorable, role.

[4] Six years later, Pierce was able to use a design closely resembling his original version when he worked with Lon Chaney Jr. on The Wolf Man.

3 (Les préludes) by Franz Liszt is also heard, as well as compositions by Heinz Roemheld from the earlier Universal horror films The Invisible Man (1933) and The Black Cat (1934).

Pierce's minimalist werewolf makeup has been referenced and duplicated in other productions, including Wolf (1994), with Jack Nicholson, as well as the television series Penny Dreadful.

In 1977, a paperback novel written by Walter Harris, under the pseudonym "Carl Dreadstone",[12] was published as part of a short-lived series of books based on classic Universal horror movies.

The second novelization, written by Carl Green, was published in 1985 as part of Crestwood House's hardcover Movie Monsters series, which was also based on the old Universal films.