The Drashani Empire – a galaxy-spanning civilisation, the glory of Rome set among the stars. But for decades now, the Royal Houses of Gadarel and Sorsha have been at war, each claiming the Imperial throne. The wedding of Prince Kylo and Princess Aliona was meant to change all that – a blessed union between the Houses, a new hope for the Empire. Until Aliona's wedding galley crash-landed on the planet Sharnax – and all contact was lost. The TARDIS lands aboard the ship carrying the fiery Kylo in search of his lost princess – but with a sabre-toothed monster roaming its corridors, the Doctor soon discovers he's not the only alien presence aboard.