Set in 2068, the series depicts a "war of nerves" between Earth and the Mysterons: a hostile race of Martians with the ability to create functioning copies of destroyed people or objects and use these reconstructions to carry out specific acts of aggression against humanity.
Earth is defended by a military organisation called Spectrum, whose top agent, Captain Scarlet, was murdered by the Mysterons and replaced with a reconstruction that later broke free of their control.
"Dangerous Rendezvous" is one of four episodes that were later re-edited and combined to create Revenge of the Mysterons from Mars, a Captain Scarlet made-for-TV compilation film produced by the New York office of distributor ITC Entertainment in 1981.
After Scarlet's jet crashes and explodes, he is picked up in an empty car under Mysteron control and driven to a remote shack containing a pulsating glass screen, behind which Captain Black is sitting.
Seconds before midnight, White decodes Scarlet's message and orders Ochre to shoot out one of the base's observation windows and jettison the crystal, which explodes harmlessly in the atmosphere.
[6] Anthony Clark of sci-fi-online.com comments that while its pace "could hardly be described as breakneck", "Dangerous Rendezvous", along with "Crater 101" and "Shadow of Fear", helps to "progress Spectrum's fight back against the Mysterons".
[8] Chris Drake and Graeme Bassett argue that the scenes of White, Scarlet and Blue explaining Spectrum's communications to Dr Kurnitz add interest to the episode.
[9] Media historian Nicholas J. Cull suggests that the premise was inspired by contemporary events, writing that the possibility of peace between Earth and Mars reflects "shifting attitudes" in the Cold War.