Deep in the Mariana Trench a survey team encounter the TV-21, a prototype Thunderbird vehicle that was flown by Jeff Tracy, when a systems failure causes the ship to be stranded on the seabed. International Rescue arrives to rescue the crew but the Mechanic suddenly takes control of the surveyor and uses it to crush Thunderbird 4. Gordon gets out just as his ship is destroyed and now must use the TV-21 to rescue the crew. Meanwhile, Lady Penelope and Parker are investigating into how the Hood is communicating with the Mechanic.
The XN Surveyor scanning the Mariana Trench
The crew compartment of the XN
"The Mariana Trench is the last unmapped ocean there is. So you two will be down there until the job is done or money runs out"
"That's not likely. XN Industrial is swimming in cash"
"Where research grants are concerned, you don't ask questions"
"Huh? Object detected.. Titanium alloy."
"It's part of an aircraft"
John picks up the distress signal from the XN company about their missing surveyor
"A deep ocean survey team just lost contact with their control base"
"I'm receiving the footage of their final transmission now"
"TV-21? No.. It can't be!"
"Scott, are you OK?"
"Yeah, you look like you've seen a ghost"
Scott send the footage to the holo table in the centre of the room so everyone can see
"Uh, is anyone gonna clue me in here?"
"It's the first Thunderbird"
"More of a prototype really, until it c-crashed. Your father thought the wreckage would be lost forever"
"We also have a rescue to deal with. Thunderbirds 2 and 4, suit up. Gordon, you're going swimming"
"Hm, interesting.. This could be exactly what we've been looking for"
Parker is serving Lady Penelope tea
"Haven't we forgotten someone?"
"Begging your forgiveness your mongrelship"
Parker puts sugar into Sherbet's tea
"Hello John. Joining us for a cup?"
"Remember when you asked me to keep an electronic ear on Parkmoor Scrubs Prison? I detected a strange signal coming from the area"
"Only a blip and then it was gone"
"Do you think it's the Hood sending a message?"
"Surveyor located, craft appears intact"
"It's International Rescue!"
"I've made visual contact with the crew, no apparent injuries"
"The ship sure is a weird-looking thing. There's no signs of external damage"
"Gordon, what about the TV-21? Have they found part of the wreck?"
Thunderbird 4 moves in to clear some of the rocks covering the prototype
"It's not just part of the wreck..."
"Why is everyone making such a big deal about a wrecked plane?"
"The first ever Super-Mach 20 ship. It was the prototype to Thunderbird 1"
"Dad had to abandon the plane somewhere over the Mariana Trench, rather than let that villain get his hands on it. I remember it broke Dad's heart"
"And now these guys have randomly stumbled upon it?"
Parker breaks the door down to an abandoned factory near the prison
"For an abandoned warehouse, this building draws a lot of power"
"I believe the word your looking for is 'Bingo'"
"V-Very smart of you to track that signal, John."
"We got lucky"
"It seems the Hood may be up to his old tricks"
"I've seen engineering like this before. It's the w-work of the Mechanic"
"Then it proves without a doubt he's in league with the Hood"
"I b-better show the others immediately"
"Th-that's the entire TV-21! It hardly looks d-damaged at all!"
Brains notices the craft's company logo
Brains compares it to the data he received from Lady Penelope
"Thunderbird Four! G-Get out of there!"
Gordon manoeuvres Thunderbird 4 away to avoid the Mechanic's grasp
The Mechanic's machine's arms grab a hold of Thunderbird 4
The arms begin to crush Thunderbird 4, even though Gordon has full power in the emergency jets
"Well you better come up with something fast, Thunderbird 4's hull integrity is failing"
Gordon attempts to cut Thunderbird 4 free using the plasma cutter
The Mechanic switches his suit's controls over to his underwater drones
The ray-mechas begin to attack Thunderbird 4
One of the mechas shorts out the plasma cutter of Thunderbird 4
With the still functioning claw arm, Gordon attacks the mechas that come towards the craft
"My dive suit won't take the pressure at this depth"
Gordon begins to equip his deep water exo-suit, while the hull of Thunderbird 4 is getting crushed around him
"Hull integrity 28%. Gordon what are you doing?"
The Mechanic successfully crushes Thunderbird 4
"Thunderbird 4... is offline"
Gordon escapes and watches
Thunderbird 4 is broken into two halves
Gordon gets knocked around after trying to fight the Mechanic
The XN craft travels over Gordon towards the TV-21
The Mechanic's craft then starts to dredge up the TV-21
"The surveyor's going for the TV-21! He's stealing dad's ship!
"Searching the whole Mariana Trench was too b-big a task for the Mechanic alone, so he secretly gave this team the equipment for their m-mapping expedition"
"Looking at these p-plans, it seems the Deep Ocean Surveyor has a centralised p-power system"
Gordon swims towards the Mechanic's craft
Gordon goes in to try and cut the ship's power
One of the XN's mechanical arms closes in on Gordon
Gordon fires a charged pulse beam at the power system
The craft is rendered powerless and it collapses on the ocean bottom
"Now what? The life-support systems have powered off"
"Only Thunderbird 4 could survive the pressure this deep, and it's seriously out of operation"
"We can use the TV-21! Gordon could restart it and then use the thrusters to p-power both vehicles to the surface"
"I've always wanted to fly dad's plane!"
Gordon opens the hatch to the TV-21
Gordon's face light up as he enters the TV-21's cockpit
Gordon starts to sit down only to find something on the seat
"Man, I can't believe we used to wear these things"
"Sorry to spoil the moment Gordon, but hurry?"
"Stopped first time too. Got any other ideas?"
"You could try the 'Jeff Tracy' fix. After all, it is dad's plane"
Gordon gives it the old 'Jeff Tracy fix' by banging once hard on the console button
The TV-21's engines stay functioning
Using the TV-21's engines, Gordon manages to start lifting both crafts to the surface
"Three hundred meters from surface"
Thunderbird 2 grapples both craft and help bring them the rest of the way to the surface
Gordon climbs over the Mechanic's ship to rescue the trapped crew
"It's okay, you're safe now"
"Thank you International Rescue"
The crew are lifted into the safety of Thunderbird 2
"So tell me, what was it like flying dad's plane?" "It was awesome!"
"If we can get into the system, maybe we'll learn more of what the Hood and the Mechanic are up to"
Lady Penelope discovers that The Mechanic has hacked into the transmissions to and from Tracy Island and is listening to every word
"Wait. He needs to hear this first"
"To the Mechanic: let me tell you who you're dealing with! We're International Rescue, you can't push us around!"
"And you absolutely, positively can't take our stuff!"
"I'm the Mechanic. I take what I want from who I want, whenever I want it"
The Mechanic's craft regains power
The ship powers up and breaks free of the cables that were holding it in the air
"International Rescue, we have a situation"