An American intelligence agent, aided by a Chinese-American female agent, uses a time-travel belt to thwart Chinese operatives who are attempting to import to Los Angeles the materials to make an atomic bomb.

Agents Napoleon Solo and Illya Kuryakin work for a secret intelligence service working under the auspices of the U.N. Their immediate superior is Mr. Waverly. Together they operate out of a secret base beneath the streets of New York City, and accesses through several cover business such as Del Floria's Tailor Shop and the Masque Club. This secret intelligence service is called U.N.C.L.E. United Network Command for Law and Enforcement.