World Securities was an international private security company that used super-advanced technology to help its agents solve its cases. The series "rotated" through three different agents, who were part of the Probe Division and thus called "Probes," with only one appearing per episode (although all three actors were listed in the opening credits). Probe Division dealt with items that went missing: people, diamonds, information, etc. The three agents were: Hugh Lockwood (ex-astronaut and Lead Operative), Nick Bianco (head of Omega Division, involved with organized crime), and C.R. Grover (Standby Probe, available for emergency back-up). Their immediate supervisor and the creator of all the electronic gadgetry was V.C.R. Cameron, who monitored their activities from home base, while Gloria Harding was in charge of their medical readings. Each agent carried a combined telemetry unit/medical scanner/miniature camera that they could mount on a ring or tie-tack. They also had a dental implant that allowed them to send brief coded signals back to base by clicking their teeth, and a radio transceiver implanted in their ear. In theory they were in constant contact with home base where Cameron would coordinate their efforts, provide advice, and give them real-time information from the extensive computers. Each agent was also a highly competent fighter, driver, and investigator, capable of operating on their own when something would (inevitably) go wrong with their link to World Securities.

(l to r.: Burgess Meredith, Hugh O'Brian)