This Is My Mark

Billy is an archaeological pre-historian - a long-haired, wiry and slightly smelly obsessive who is strangely attractive to women. He's convinced there are cave paintings beneath the Welsh Mountains, paintings as magnificent as the Ice-Age treasures of France at Lascaux and Chauvet.

Ness Hawkes is a pot holer with a bit of a reckless streak. If it's an adventure filled with death-defying terror then Ness is your woman. Close on their trail, having abandoned their yoga mats and leotards in favour of day-glo cagoules, are Billy's wife Sarah and her friend Pam. But a third pair is also in the race to track down the elusive cave paintings: a villainous showman and his sidekick hope to exploit the caves and their contents and turn it into a virtual theme park.