The TARDIS arrives in 1920s England, the Doctor, Jamie, Ben and Polly finding themselves beside a railway line. The station appears deserted, but there are figures watching from the shadows, all of them waiting for a dead man's train.
The Doctor, Jamie and Victoria join a survey team to find out why on the planet Amyrndaa where everything is suited to creating life, nothing lives for long.
When tempers fray in the TARDIS, the Doctor struggles to help Jamie and Zoe resolve their differences. Arriving at Aspen Base proves a welcome distraction, but the isolated facility is under siege.
The Edge is just the sort of place to interest the Doctor and Zoe. However, a secret lies hidden in The Edge laboratories. Jamie instinctively knows that something is wrong, and it doesn't take long for him to be proved right.