Edwin Richfield

Steed hangs up his stocking, Emma asks for more.

Secrets are leaking from a defense research establishment, thanks to a new invention: an eavesdropping device which can use any shiny surface to reflect and amplify sound waves. But with Steed unavailable, Tara must investigate with only an inexperienced new agent for support.

Mestor’s true plan is revealed and the Doctor's old Gallifreyan friend Azmael comes to the realisation that he has been corrupted long enough by the Gastropod leader.

A disfigured tycoon tells Peter he wants to become invisible, but his motives have political implications.

Mestor claims that all he wants is for the Sylvest twins to help him repopulate his home planet but the Doctor knows there’s more to this than meets the eye.

On Jaconda, Mestor’s cruel domination over the planet's population continues while on Titan Three, the Doctor seems to have been blown up in a booby-trapped building.