The native British crayfish are in danger. Their rivers have been taken over by larger, more aggressive American signal crayfish, which are spreading a deadly disease. The situation underwater is spiraling out of control. This short film tells this surprisingly grim ecological story in the style of a zany pseudo-documentary—complete with crayfish gangsters, retired crayfish, plague doctors, and melodramatic interviews. The film combines real-world challenges of species conservation with costumes, puppetry, and dry humor, while posing an important question: Can Britain’s often-overlooked freshwater inhabitants survive this catastrophe?