When the Doctor and Mel arrive in the Space Trading Colony, Iceworld, the Doctor can feel that there is mischief afoot. And he and Mel don't have to wait long before they discover the culprit, for there in the Refreshment Bar they meet up with that old intergalactic rogue, Sabalom Glitz. Glitz is hot on the trail of a hidden treasure and the Doctor, keen to do some scientific research, decides to join him. Down into the Ice Passages they go - through the Ice Garden, past the Singing Trees, beyond the Lake of Oblivion - in search of the Dragon's Treasure. But the Doctor and his companions don't know the true worth of this mythical hoard. Only Kane, the most feared man in Iceworld, knows the secret of the Dragonfire...

'If this is a top secret naval camp, I'm Lord Nelson!' Ace has a poor opinion of the security arrangements at Commander Millington's North Yorkshire base - and she's less comfortable in 1940s fashions. But the Doctor has graver matters on his mind. Dr Judson, inventor of the Navy's ULTIMA code-breaker, is using the machine to decipher the runic inscriptions in the crypt of the nearby church. Commander Millington is obsessed with his research into toxic bombs that he insists will hasten the end of World War Two. A squad of the Red Army's crack Special Missions brigade lands on the Yorkshire coast with instructions to steal the ULTIMA device - unaware that Millington has turned it into a devastating secret weapon. And beneath the waters at Maidens Point an ancient evil stirs... The Doctor uncovers mysteries concealed within villainous plots - but what connects them all to a thousand-year-old curse?