Christopher H. Bidmead wrote Hollows of Time as a sequel to Frontios, so it has Tractators, time tunnels and the Gravis, this time in a contemporary English country village with a villain called Mr Stream who, for licensing reasons, is not the originally planned anagram. Like all Bidmead's stories it's a bit incoherent and we really do miss the visuals (despite the smart framing device of Six and Peri telling each other the story once safely back in the Tardis) but there is some lovely characterisation; Susan Sheridan, the original Trillian from the Hitch-hiker's Guide, plays both an old lady and a young boy very effectively. ( )