Whilst going to the Get good at, that has been exiled to a luxurious castle prison on a small island, Doctor Who and Jo Grant learn a number of boats have got vanished in the region. Whilst looking into these mystical disappearances, Jo and the physician are attacked with a Sea-Devil, among a submarine colony distantly linked to the Silurians. Quickly they discover that the Sea-Devils intend to conquer the Earth and enslave humanity, aided and abetted from the Grasp. What can Doctor Who do to avoid them? Geoffrey Beevers, who performed an incarnation of the Expert in the classic BBC Television series, reads Malcolm Hulke’s comprehensive and unabridged novelisation, 1st published by Target Books in 1974.