Stephen Boyd heads a team of scientists sent on a bizarre experimental mission. Through a revolutionary and as-yet untested process, the scientists and their special motorized vehicle are miniaturized, then injected into the blood stream of a near-death scientist (Jean del Val). Their mission is to relieve a blood clot caused by an assassination attempt. One member of the expedition is bent on sabotage so that the scientist's secrets will die with him. Another member is Raquel Welch, seemingly along for the ride solely because of how she looks in a skintight diving suit. The film's Oscar-winning visual effects (by Art Cruikschank) chart the progress of the voyagers through the scientist's body, burrowing past deadly antibodies, chunks of tobacco residue in the lungs, and other such obstacles. Oscars also went to Jack Martin Smith and Dale Hennesy's art direction and Walter M. Scott and Stuart A. Reiss' set decoration. Fantastic Voyage was later spun off into a Saturday morning cartoon series.