Spectrum and the lunar authorities have made plans for the Mysteron complex in Crater 101, on the far side of the Moon, to be destroyed with a nuclear device. However, to prevent the Mysterons from simply reconstructing the complex, its power source will first have to be located and removed.
Having volunteered for this dangerous mission, Captain Scarlet, Captain Blue and Lieutenant Green return to the Moon and set off from Lunarville 6 in a Moonmobile. Arriving at Crater 101, they transfer to a smaller Lunar Tractor and make their final approach to the complex. Automated sentry vehicles move to attack them but are immobilised when Green destroys the control vehicle with the tractor's rocket launcher. Donning space suits and entering the complex, the Spectrum officers discover the power source to be a pulsating crystal surrounded by machinery.
The CB29's arrival reminds Scarlet of the inscription on a good luck charm given to him by Nolan: in 2058, she oversaw the launch of a Neptune-bound CB29 space probe that reached its destination "ahead of schedule". Remembering this phrase, Scarlet realises that the nuclear device will detonate prematurely. He orders Blue and Green to return to the Moonmobile and clear the area while he attempts to extract the crystal. Will he succeed?
Another entertaining Scarlet episode, though a little slow moving. Great set-pieces, puppeteering and a gritty approach to this brand of TV Series. There's some fine action.