Tusk follows Wallace Bryton, a brash and arrogant podcaster who travels to Canada to interview viral internet personalities for his show. When his plans fall through, he discovers a strange personal ad from an old man named Howard Howe, who promises wild stories of his past adventures at sea. Wallace, intrigued by the bizarre opportunity, decides to meet him at his remote mansion deep in the woods.
Howard initially appears as a charming and eccentric gentleman, sharing fascinating tales from his life — including one about being saved by a walrus during a shipwreck. But as Wallace settles in, things take a dark and disturbing turn. Howard drugs him, and Wallace wakes up to find himself held captive with his leg amputated. It becomes clear that Howard has sinister intentions.
As Wallace endures psychological and physical torment, Howard reveals his twisted plan: to surgically transform Wallace into a walrus as part of a demented tribute to the creature he once loved. The horror escalates as Howard systematically mutilates Wallace, stripping him of his humanity both mentally and physically, forcing him to “become” the animal.
Meanwhile, Wallace’s girlfriend Ally and best friend Teddy grow suspicious after losing contact with him. They team up with a peculiar former detective, Guy Lapointe, who has been investigating similar disappearances. Their search leads them through odd clues and finally to Howard’s home — but by the time they arrive, Wallace has already undergone a horrific transformation.
In the end, the rescuers kill Howard, but Wallace is beyond saving. Left physically and psychologically broken, he is placed in an animal sanctuary, living out his days in a walrus enclosure. Tusk concludes on a haunting, tragic note, blurring the line between man and monster, and offering a surreal, disturbing meditation on obsession, identity, and isolation.