An alien intelligence hitches a ride onboard the TARDIS to 15th century Italy, where a deranged astrologer attempts to harness its power.
Tom Baker
Elisabeth Sladen
Jon Laurimore
Antony Carrick
Gareth Armstrong
Tim Pigott-Smith
Norman Jones
Robert James
Brian Ellis
Pat Gorman
James Appleby
John Clamp
Peter Walshe
Jay Neill
Peter Tuddenham
Peggy Dixon
Jack Edwards
Alistair Fullarton
Michael Reid
Kathy Wolff
Stuart Fell