The Third Day follows Sam, who after being drawn to a mysterious Island off the British Coast, is thrown into the unusual world of its secretive inhabitants. Isolated from the mainland, the rituals of the island begin to overwhelm him, and he is confronted by a trauma from his past. As the line between reality and fantasy blurs, Sam finds himself immersed in an emotional quest which puts him at odds with the islanders and begins to threaten their way of life.