Survivors of a tragic shipping collision are rescued by a mysterious black ship which appears out of the fog. Little do they realise that the ship is actually a Nazi torture ship which has sailed the seas for years, luring unsuspecting sailors aboard and killing them off one by one.

The story revolves around the lost planet Shada, on which the Time Lords built a prison for defeated would-be conquerors of the universe. Skagra, one such inmate, needs the help of one of the prison’s inmates. He finds nobody knows where Shada is anymore except one aged Time Lord who has retired to Earth, where he is a professor at St. Cedd’s College, Cambridge. Luckily for the universe, Skagra’s attempt to force the information out of Professor Chronotis coincides with a visit by the professor’s old friend, the Fourth Doctor.

Abelard, a famous teacher of philosophy at the cathedral school of Notre Dame, falls in love with one of his students, Héloïse d’Argenteuil. A sixteen-year old girl raised in a convent, Héloïse has an intellectual curiosity and rebels against the status of women in 12th century Europe. When others begin to suspect their relationship, Heloise’s uncle Fulbert and the bishop of Paris work together to put a stop to it. Héloïse becomes pregnant with Abelard’s child, and they are married in secret. Abelard struggles for acting against the will of God, yet is unable to escape his love for Heloise.

Elderly Scott kills himself after a heart attack wrecks his body, but then comes back as a ghost and convinces his loving young hot wife Kate to pick and kill a young man in order for Scott to possess his body and be with her again.