Molly Root braces herself against the bulkhead as the jet starts to lose altitude. Somewhere behind her, in the cockpit of the plane, the pilots must be desperately trying to restart the engines. They won't be able to, she thinks. No way to do that now she has access to the main control systems.

If the jet were a stone, they'd all have less than a minute to live. They'd hit the English Channel, directly below them, at around a thousand miles an hour, and explode like an egg thrown at a concrete slab. But the plane has wings, and plenty of forward momentum: the pilots will be able to fly it like a glider for some distance. Perhaps even to safety.

If she lets them. The power to kill or save everyone onboard is literally in the palm of her hand.
It's suddenly very quiet and still in the main cabin. Everyone is looking at her. Murray's mouth opens and closes, like a fish. "But…" he says. "But-"

Graves cuts him off. "What have you done?"
Even as he speaks the pilot's voice comes over the intercom. "Sir, we have a serious problem – we've lost both engines."

Graves leans over the table and hits the intercom button. "Stand by. Keep us steady. You can glide this thing, right?"

"Yes sir, but– "

"Keep doing that." He looks at Molly again. "I think we're about to find out how to turn the power back on. Right?"

Molly looks back at him, coolly. "That's right."

She'd come up with the idea while looking at pictures of Murray's plane. If Drake's car could be hacked into, why not a jet? She takes the phone out of her pocket, holds it up so they can see.

"Your plane's run by a computer, Jon. A UNIX hub, actually. It controls the engineering network, the telemetry, everything. Now, you're not supposed to be able to access the computer remotely – it's only supposed to transmit data, not receive it – but there's a way round everything. The technique's called shovelling the shell, if you're interested.
"I have root access to the operating system. I already killed the power. I can crash this plane any time I like, with a single command. Once I give that, there's no going back. So you need to do what I say, and quickly." Her thumb hovers over the SEND key. Murray has gone white under his Seychelles tan. "But – you'll kill yourself! Turn it back on!" The voice is an indignant squeak, now.

Molly laughs at him. "You're planning to kill me anyway, or at least torture me in some secret dungeon. That's where this flight ends up for me. But this way, I get to avenge Danny. Ask your man there if I'm serious."

Murray looks at Graves, who nods slowly. "I don't think she's bluffing."

"Lionel, make her stop it. Hurt her if you have to. I'll pay you anything you like."

Molly shakes her head. "Take a step towards me – stand up, even – I press the button." She points at Sawyer, Raghuveer and Brody. "You too. Strap yourselves into your seats, lads. This could get bumpy."

Graves says, "What do you want?"

Molly says, "The USB drive you took from me in the van. It contains a copy of the data Danny stole, and one other thing. Plug it in to the laptop, and give it to Murray."

Graves reaches down, gets his rugged, rubberized military-issue computer, and boots it up. In the powerless, gliding jet, the warm-up sequence seems to take an age. He finds the USB stick, plugs it in, and passes the laptop over to the CEO.

"Decrypt the files," Molly says. "Now. Or I drop us."

"I don't know the password!" says Murray. But he's lying. She can read it in his eyes.

"Last chance," she says. "Don't lie to me again."

Murray looks at Graves again, sees nothing to help him, and then back at Molly, holds her gaze for a second. Then he begins to type, and Molly lets out a long, shuddering sigh.
There's a soft chime as the decrypt finishes. Molly says, "Kick the computer over to me. It looks like it can take it."

Graves kicks the laptop over to her. It leaves grooves in the deep pile of the carpet. She crouches down to pick it up, keeping an eye on the men at all times. She thinks she can see a half-smile on Raghuveer's face, the first bit of emotion he's betrayed since she saw him for the first time; Sawyer is glaring fiercely at the ceiling. Brody's eyes are closed, his mouth working. Is he praying? Molly thinks. Weird, for a killer. Most importantly, nobody makes a move towards her.

She sits down, cross-legged, the screen open in front of her. In the file browser, she can see a huge archive of emails – thousands of them. She parcels them up into a .zip file and piggybacks on the jet's communications system to send them out via email. It takes less than a minute, and the data that will bring down Jonathan Xavier Murray is in Piotr's hands, somewhere.

In her mind, a final stone drops on to the board; a polished black pebble in a sea of white, changing the pattern. We did it, Danny. We nailed them.
She says, cheerily, "OK. Thanks for that. There's one last thing…"

Molly opens up one last file from the USB stick. It's a word-processor document entitled 'Jonathan Murray: a confession.' She leaves it on the screen, kicks the laptop back to Graves. "You're going to record that on video, and I'm going to send it out to the news media, along with the files that prove what you did. And then I might think about turning the engines back on.
"I want you to remember: I'm still in control of this plane. I can crash us on landing if I think you're going to try anything. Don't make me do that. And I reckon I should tell you where we're landing…"

***

Piotr Sevchenko: sitting in a bar at Paris's Orly airport, sipping a coffee and watching his email on his slate. The files had come in from Molly on schedule, and he's already writing the press release. There's a beep, and a video file drops in to his inbox. Well done, kid, he thinks.
He plugs in his headphones, double clicks the attachment, and finds himself looking at Jonathan Murray, looking pale and agitated, talking into the camera. His forehead is slick with sweat; his glasses slightly askew. "My name is Jonathan Xavier Murray. I'm the acting CEO of Murray Petroleum. Earlier this year, I entered into a corrupt and illegal contract to dump toxic waste in a developing nation. The files that prove my involvement with, and full knowledge of, this deal are being disclosed to you now, by the group known as Damocles.

"In an attempt to cover this up, I ordered the killing of a teenage boy, called Daniel Solomon. I employed a private military security company to carry this out, with the help of a corrupt police officer. I am guilty of murder and ask that I be taken in to custody at the earliest opportunity. To that end, my private jet is about to land in Paris, where I will hand myself and my accomplices over to the authorities.
"The facts are these…" And Murray lays it all out. Times, dates, people. Piotr watches to the end, and sends an email to Molly's phone. Good work. We've got everything we need. He makes a package of the confession, the email archive, and a few other things – everything they'd collected on Drake, Graves, even Erica Jonsson. He sticks it all in an email and sends it to as many journalists and news agencies as he can think of. A lot of jail time there, he thinks.

His second cup of coffee isn't even luke-warm by the time the breaking news hits the television screen above the bar. Five minutes later, armed police march past the entrance in riot gear, towards the arrival gates.
Stay safe, Molly Root, Piotr thinks. He drains the coffee, stands up, and strolls towards the airport's exit. I hope you'll forgive me when they tell you what this was really all about. He dials a number and puts his phone to his ear as he steps out into bright sunshine. "Hey. Boss. Da. She's coming in now. Runway 6, I think. They've cleared everything for her. Look, make sure she doesn't get any hassle, yes?" He listens for a moment, smiles. "Thanks. She's quite the find."

He hails a cab, climbs into the back, and says, "L'Ambassade de Grande Bretagne, s'il vous plaît."

The final instalment of Root will be available on Friday. If you can't wait until then, take the Acenet challenge to see if you have what it takes to join this secret world. Then join the discussion on our Facebook page and test your wits against the top Acenet members