BBC1 premieres the 35th episode of Terry Nation’s science fiction series Blake’s 7. This episode, written by fantasy novelist Tanith Lee, is unique in that it features only the regular cast with no speaking guest stars. 
After visiting a derelict alien “tomb-vessel,” Cally is inhabited by the soul of a long-dead creature who begins to take her shape, draining her of her energy, and takes over the ship and, one by one, the crew – except for Avon, the one member of the crew who is determined not to surrender into slavery. But the alien possessing Cally has predicted Avon’s presence and his resistance.
written by Tanith Lee
directed by Fiona Cumming
music by Dudley SimpsonCast: Paul Darrow (Avon), Jan Chappell (Cally), Michael Keating (Vila), Steven Pacey (Tarrant), Josette Simon (Dayna), Peter Tuddenham (Zen, Orac)
LogBook entry by Earl Green