The planners of the world’s greatest engineering feat – the flooding of part of the Sahara Desert – knew nothing of the life that teemed below their New Sea. But for the accident which plunged Mark Sunnet and his girlfriend Margaret into a cavernous world, nothing would have been known of the catastrophe which now threatened the survivors of an ancient race. Mark and Margaret had to escape the endless caverns in which the secret people kept them as prisoners under threat of execution – and escape the merciless New Sea which would kill them all. Cover art by Don Ivan Punchatz.