Secret agent Cool McCool was assigned the task of apprehending some of the world's most eccentric villains. He was under the directive of a cigar smoking boss called Number 1, who was only ever seen by viewers as an arm extending from the back or side of the chair that hid his face. Like all good secret agents, McCool was outfitted with numerous handy gadgets that served more than one purpose: he had a gun that doubled as a phone, a watch that doubled as a phone, a mustache that doubled as a phone... In emergencies McCool actually pulled out gadgets that didn't function as a phone, but they always backfired due to his faulty implementation. Perhaps the most reliable tool of his trade was the Coolmobile, a multipurpose vehicle that could transform into different modes of transportation. Other members of the agency to make an occasional appearance included Riggs — the developer of McCool's gadgets, Breezy — McCool's sometimes sidekick, and Friday — Number 1's dumpy secretary.
So why the name "Cool"? Cool fit McCool's name because he didn't panic. When things looked grim he remained cool under pressure, never minding that whatever action he took was largely ineffective. But results matter more than technique, and putting aside that his cases were resolved more from luck than skill, McCool captured every criminal he tracked down. Of course, those very same villains — Hurricane Harry and Bellows Belle, the Owl and the Pussycat, the Rattler, Jack-in-the-Box, Dr. Madcap and Greta Ghoul — returned again and again in subsequent episodes to further their nefarious plots.
Each half-hour episode consisted of three short segments. The first and last segments featured Cool McCool, while the middle segment followed the adventures of McCool's father, Harry McCool, and his two brothers, Dick and Tom, as three inept police officers patterned after the Keystone Kops.