Terence Clemons, a schoolteacher, old friend of Doctor Metrevelic, and an expert in hypnotism, asks for his help as well as that of Zagor and Chico, to solve the mystery behind a series of disturbing deaths in Asher Mill, an isolated village in the mountains. The victims (a young woman named Drew and Darius, the farmhand of a man named Jonathan) appear to have been torn apart by a savage beast. Some claim that the culprit is a werewolf. Terror grips the village as the next full moon approaches…
Following the trail of the werewolf, which fled into the forest after killing Reverend Stone and being wounded by Zagor with a silver cross, the Spirit with the Hatchet reaches a cabin in a forest clearing that seems to hold the key to the mystery. It is the home of three quarrelsome giant lumberjack brothers: Louis, Matt, and Derek Rhodan. One of them, Matt, bears the marks of Zagor’s earlier fight with the werewolf.
But the werewolf suddenly appears and kills all three brothers, only to be mortally wounded in turn by a silver dagger forged by Zagor. When the monster’s body is found, Zagor discovers that it is Jonathan the farmer.
But has the werewolf threat truly ended? That night, Tawar, the Tunican shaman who died in The Assassin of Darkwood, appears to Zagor in a dream and tells him that “one is the howl, but many are the wolves,” advising him to seek “someone who teaches others to read the signs.” This means there is more than one werewolf: Matt Rhodan, Jonathan the farmer, and… who else? Moreover, the wolf-men seemed to target specific victims, as if there were a single mastermind behind them.
The crucial insight comes from Doctor Metrevelic: in Asher Mill, the only person who “teaches others to read the signs” is Professor Clemons himself. Exposed, Clemons gives one final hypnotic command to the last werewolf: Martin, Drew’s boyfriend and one of the first victims. Martin transforms and begins battling Zagor until both plunge into a raging river. Zagor survives, while the werewolf falls from a high waterfall.
Meanwhile, Professor Clemons attempts to flee but becomes trapped in a bear trap that severs a major artery. Before dying, he confesses that his obsession with lycanthropy led him to develop a serum capable of transforming humans into wolves, activated by a “catalyst” in pill form and the rays of the full moon.
Using his hypnotic abilities, he controlled the werewolves. But one of them slipped beyond his control and killed Darius, Jonathan’s farmhand. The villagers of Asher Mill had turned to Clemons himself to free them from the curse, and to avoid suspicion, he had been forced to seek Metrevelic’s help.
The story ends on a partially happy note: it is revealed that young Martin survived the fall from the waterfall and, by no longer taking the catalyst pills, will never transform into a werewolf again.
