In this documentary by Errol Morris, four men with unique vocations are interviewed. There's Dave Hoover, a lion tamer; George Mendonça, a topiary gardener; Ray Mendez, a hairless mole rat expert; and Rodney Brooks, a robotics designer. Using a special camera called the Interrotron, each of these men is able to talk about his obsession seemingly directly to the audience, while Morris inter-cuts the interviews with stock footage and movie clips that are used to draw connections between them all.