breaks into the Culver Atomic Centre but is discovered by security guards. While making his escape he is forced to enter a radioactive area, where he is exposed to an isotope that renders him detectable on long-range Geiger counters for the next 48 hours. In a bid to capture the Mysteron agent, Spectrum search the surrounding area using a fleet of Detector Trucks aided by the Angel fighter squadron. Trapped inside the search area, Black murders a filling station mechanic to steal the hidden Spectrum Pursuit Vehicle that he is guarding. When Captains Scarlet and Blue arrive to requisition the SPV, they encounter the Mysteron reconstruction of the mechanic, who pulls a gun on them but is shot dead by Scarlet. The Detector Trucks pick up Black's trace as he speeds down a highway in the SPV. Captain Ochre sets up a roadblock to stop him. However, the Mysterons warn Black and order him to return to the atomic centre, where the background radiation will make him undetectable to Spectrum. Sighting the SPV from the air, Symphony Angel lands her fighter. She is captured by Black, who uses the SPV to crash the atomic centre's gates and takes Symphony deep into the complex. The Spectrum forces converge on the atomic centre. Black attempts to kill Symphony by exposing her to increasing levels of radiation, but ultimately chooses to spare her life. He instead forces the Angel, who is now radioactive herself, to drive out of the complex alone in the SPV. Thinking that Black is the driver, the Spectrum forces begin a pursuit. The entrance to the complex is left unguarded, and Black decontaminates himself and slips away. Symphony crashes the SPV and Spectrum discover too late that they have been tricked. After Colonel White's debriefing, Lieutenant Green discreetly asks Symphony why she did not alert the Captains of her presence during Black's escape; she admits that she had never driven an SPV before and did not want to bypass such an opportunity.
Production
"Manhunt" marks the first contributions of voice actorDavid Healy to the series, here providing the voices of a Spectrum geiger counter operator and one of the Culver Atomic Centre security guards. The mechanic's radio plays the theme music for Gerry Anderson's film Crossroads to Crime. The episode's original incidental music was recorded during a four-hour studio session held on 16 April 1967 with a group of 14 instrumentalists. This music runs for four minutes and seven seconds. Music for "Big Ben Strikes Again" was recorded during the same session. Spectrum makes a second attempt to capture Black in "Treble Cross", which re-uses footage originally recorded for this episode. This footage includes scale model shots of the Spectrum Detector Trucks, which were designed by special effects assistant Mike Trim. The puppet-scale interior of the trucks was adapted from the Zero-XMartian Exploration Vehicle cockpit that was originally built for the film Thunderbirds Are Go and last seen in "The Mysterons".
Reception
, Martin Day and Keith Topping, authors of The Guinness Book of Classic British TV, consider "Manhunt" to be one of several Captain Scarlet episodes that "seem little more than left-over Thunderbirds scripts". Andrew Pixley and Julie Rogers of Starburst magazine regard Black's murder of the mechanic as one of the series' more violent moments, noting that Black kills another filling station worker in "Special Assignment".
