THUNDERSTONE Synopsis Herne and Ashley Templar's Aunt Sophie is missing on her return from an underwater archaeological expedition to find the 'Lost City of Tiahuanaco', in Lake Titicaca, Bolivia. When searching through a trunk containing her forwarded belongings they are surprised by a mysterious green crystal globe, and find a coded diary that they feel have been left as clues to her whereabouts. An old colleague of Sophie's, an eccentric Professor Rameses Richardson, and his wealthy sponsor Lucius van ber Berg offer to take the Templar family to Bolivia. Herne and Ashley travel ahead of their parents on Lucius van der Berg's private jet. During the flight Lucius recounts the legend of 'Viracocha', who emerged from Lake Titicaca - 'and brought new skills but wielded awesome weapons'. It seemed that Aunt Sophie believed that the legend was true. She had also hinted that an object she'd discovered proved that the 'Lost City of Tiahuanaco' still existed under the lake. The object in some way was related to the spasmodic green meteorite showers called 'Thunderstones' by the locals. On their arrival, Herne and Ashley become aware that they are being stalked, and their belongings disrupted. It seemed that the green crystal ball in their possession might be a 'Thunderstone', and sought by others.