The Gemini Man | 1976
While attempting to recover a space capsule from the ocean, agent Sam Casey is caught in an underwater explosion that affects his DNA structure and causes him to disappear, the heretofore unknown "invisibility gene" having been activated by the radiation from the blast. Incorporating a sophisticated subminiature "DNA stabilizer" in a nuclear-powered digital wristwatch, Dr. Abby Lawrence finds a way to control Sam's invisibility: when the three gold contacts on the base of the watch touch his skin, he disappears. By pressing the watch stem, Sam can change the frequency and become invisible for a maximum of fifteen minutes a day -- any longer and he will disintegrate. Stories depict Sam's assignments for Intersect (aka, International Security Technics), a CIA research office.