On Spectrum Cloudbase, Colonel White and the members of Spectrum heard an ominous voice, that they were all only too aware was coming from the Martian invaders who had been threatening earth for some time:

“This is the voice of the Mysterons. We know that you can hear us, earth men. We will no longer confine our attacks to the Spectrum organisation and earth’s defences. We will launch a pair of simultaneous attacks against the World Aquanaut Security Patrol and the London Agent of International Rescue. We are stepping up our campaign which will lead to the total annihilation of all life forms on the planet known as earth. You will pay for your unprovoked attack on our planet Mars.”

“If they only knew what hypocrites they were!” said Captain Blue, “The first Zero X mission to Mars mistook the Mysterons for pieces of rock and were just trying to cut off a sample with the laser gun. After being so badly damaged that Zero X needed International Rescue’s help to save the crew, they were reluctant to return to Mars. The later Zero X mission, manned by Spectrum this time, had three men who were more cautious and alert. Expecting an attack, they mistook a movement in the Mysteron complex for a rising weapon, and naturally fired first. For that one mistake, we’ve seen so many people murdered and replaced with Mysteron duplicates who worked against us.”

“I know it’s unfair,” said Colonel White, “But we can only do our best to stop them. I didn’t even know International Rescue had a London agent. We’ll call International Rescue and warn them, but we won’t know where to find their agent to provide our protection, and they’re not likely to tell us. We’ll have to hope we can do more for W.A.S.P.”

Deep beneath the surface of the sea, the unseen force of the Mysterons’ power killed Titan and his surface agent X-2-Zero. These two Aquaphibians had been plotting and implementing endless schemes and attacks against the World Aquanaut Security Patrol. Now they had been replaced by two Mysteron duplicates, who had observed X-2-Zero’s ability to disguise himself and infiltrate Marineville.  Now they used Mysteron science, and the duplicate X-2-Zero’s disguise skills to lure Troy Tempest, Phones and Marina out in Stingray, where the Mysterons’ powers attacked the ship and stranded it at the bottom of the sea, completely immobile, at a depth where no other craft could reach them … except one.

At Marineville, Commander Shore called International Rescue for help.

“Thunderbird Four could do it, Dad, but none of us has Gordon’s skill to pilot the craft at that depth and tow Stingray back to Marineville where the team could evacuate Stingray safely,” said Virgil.

“I guess we just can’t help. I’ll contact all the known government channels and see if anyone else has the resources,” said Jeff, “We can’t put an untrained person in Thunderbird Four to risk their life and end up having to rescue them too. In the light of what Spectrum told us, we’ve also got to worry about what might happen to Penelope. We don’t want to spread ourselves too thin.”

“Shouldn’t we guard her?” said Alan.

“We can’t just land a Thunderbird on her estate without drawing even more trouble than we’ve got,” said Jeff, “Parker’s with her, and FAB1 has a good arsenal of devices designed by Brains.”