Doctor Who: Mists of Time

The Doctor has lost his memory. But how? And why? With the help of Izzy, a Parisian from 1790, they embark on a journey to uncover the mystery behind the Doctor's amnesia. Along the way, they hope to discover what led to his memory being taken in the first place.

During their adventures, they notice a recurring phenomenon: a blue light. What is this blue light? And why does it seem to appear wherever the Doctor and Izzy go?