When the cyberattack on the rail network prevents Abby from seeing the obstacles in the sleeper's path, she realises that she's in a race against time to avert disaster.
But with Liz Draycott, the minister of transport, proving to be a less-than-ideal replacement for Joe as her onboard ally, and the so-called Driver always seeming to be one step ahead, it becomes clear that she's going to have to think outside the box to bring the train to a halt.
