Years after ending her travels with the Doctor, Vicki finds herself back in the TARDIS. The Doctor desperately needs her help, and she’s only too happy to oblige. But in the process, the two of them fall into a series of perilous encounters, with the dreaded Daleks never far behind them.

What is the mysterious presence inside the TARDIS? And precisely what damage do the Daleks and their agents intend to cause to the flow of Earth’s history?

The Doctor and Vicki must call upon all their guile and bravery to discover the truth and save the day.