This time she was rewarded with a second green light. The thick metallic chunk of steel bolts disengaging sounded as loud as church bells. As she pushed open the door, she pointed her phone at the proximity sensor on his desk and zapped it with the RFID tag. The infra-red sensor flickered a red warning light, but nowhere in Texas. Over in Vancouver, a systems operator would be dunking his cheese cruller in a mocha latte, raising his coffee in salute to the unknown agent who’d just crossed the last threshold.

Even though Caitlin knew the pressure pad just inside the door had been deactivated, she still manoeuvred around it, taking an exaggerated step to the right to avoid tripping the device. She closed the door behind her with one foot, looking for all the world like a ballerina as she did so. Or possibly a ninja who dabbled in ballet as a hobby.

With the door closed, and the last of the sensors disabled, she moved quickly. Before turning on the laptop, she plugged in the unusually heavy Siemens phone and activated the software package she’d pulled down from the satellite before leaving Temple. Agent Monroe had attended a number of Technical Services training seminars over the years, where a number of excellent teachers had attempted to instruct her at a basic level in aggressive ELINT incursion programming. She had failed every course. Caitlin had no more idea of what was happening between the phone and the powered-down laptop than your garden-variety couch potato had of the magic that delivered their favourite cable shows. But she recalled enough of the general principles to know that, somewhere inside her very smart phone, a malign assortment of software sprites were arranging themselves into a formation designed to penetrate the in-depth defences of Tyrone McCutcheon’s ruggedised Toshiba.

Complex multi-level passwords, dual factor authentication, full disk encryption and file protection were subjects she had never really understood. But she did understand that when the progress bar on the phone showed 100%, she was to turn on the laptop. Free-roaming software spiders poured out of the Siemens cell and into the target computer. As it woke up, the Toshiba’s operating system was decapitated and the disk began to boot from her phone. The digital swarm flowed over the machine’s primary defences, shutting them down before they could send out an alert to warn of unauthorised access. Utterly formidable digital ramparts crumbled as the Echelon malware interceded between the hardware’s microprocessors and the operating systems memory management unit, decoupling them, and eroding the fluid architecture before it had a chance to realise it was collapsing.