Season 16, 1978, 4 episodes
Third story in the Key to Time story arc. It’s back to Earth as the plunger of destination or whatever it’s called takes Romana and the Doctor to modern day Cornwall, England, where there’s an eeeevil sect of druids who worship standing stones that are actually silicon-based, blood-drinking, alien Ogri. The Doctor and the elderly and irascible professor Emilia Rumford learn that her partner Vivien Fay is secretly a silver space criminal, with a prison ship hidden in hyperspace. On the ship, the Doctor inadvertently releases ‘justice machines’ that put him on trial.
A nice gothic style mystery with an ingenious concept that sadly does not stick the landing, due to the jarring twist in tone from monster mystery to courtroom drama with twinkling light barristers. But, the old lady is fun (even with her odd line delivery) and there’s an important message about wearing sensible shoes on adventures.
Next up: The Androids of Tara