Having survived adventures on prehistoric Earth and the future menace of the Daleks on Skaro, the Doctor's next adventure was to be one of his most unusual and disturbing.
As a budget saving measure, a two part serial was commissioned set entirely inside the TARDIS. A creeping, shadowy, atmospheric piece was the result, featuring only series regulars.
For the first time ever, cast and crew gather to provide commentary tracks for these episodes.
Moderated by actors Toby Hadoke and Nicholas Pegg, this release features William Russell (Ian Chesterton), Carole Ann Ford (Susan Foreman), Brian Hodgson (Special Sound), Clive Doig (Vision Mixer), Richard Martin (Director), Robert Shearman (New Series Writer) and Jessica Carney (William Hartnell's real granddaughter).
Additionally there is a bonus commentary for The Roof of the World, the first episode of Marco Polo.