On a brisk winter’s morning in 1850s Yorkshire, Cuthbert, head of the intergalactic business known as 'The Conglomerate' prepares to hijack a very special train.

In the far future, his assistant, Mr Dorrick is awoken by howling alarms. There is a problem with the Quantum Gateway.

In the TARDIS, the Doctor, Romana and K9 detect strange distortions in the Vortex, an energy stream coming from a strange creature called a Laan.

The threads of a plan centuries in the making are coming together. But who is behind this plan? And can anyone possibly escape when history is against them?