This Doctor Who story, written by Ian Briggs, was first broadcast in four episodes in 1989.
The Doctor and Ace arrive at a British naval installation near Maiden’s Point on the Northumbrian coast during World War II. Befriending the base personnel, they learn that the base, run by Commander Millington, is being used as a listening post to intercept and translate German coded messages using the ULTIMA supercomputer, and to stockpile a supply of a lethal nerve gas. Meanwhile, wheelchair-bound Dr. Judson has also been using ULTIMA to help decipher Viking runes found in catacombs beneath the base, warning of a being called Fenric, which has attracted Millington’s attention believing he can gain Fenric’s power. Outside the base, the Doctor and Ace discover a covert squad of Soviet commandos, led by Captain Sorin, who are seeking to capture ULTIMA for themselves; the Doctor warns them to stay low, while Ace and Sorin become smitten with each other.
The Curse of Fenric is available on DVD.