When a werewolf bite transforms Scott McCall's life, his best friend Stiles Stilinski appoints himself as the brains of their two-man operation, researching ancient lore and acting as Scott's anchor to humanity. As they face down rival packs, monstrous creatures, and a dark spirit that threatens to consume Stiles from within, the line between their lifelong friendship and a love that could save them both is irrevocably erased.