Dusk and Dawn — Steve Elliott

Ama, Kar, Zea and Mura decide to take a relaxing cruise. While doing so, they encounter a remarkable pair of twins, oddly named 'Dusk' and 'Dawn', who are so alike that no one can tell them apart. Unfortunately, the cruise soon turns into a disaster when everyone is swept overboard by a rogue wave. Struggling to survive, Kar, Ama and Zea search in vain for Mura and then strike out for the shore. Determined not to give up hope, they search the foreshore and are thankfully united with Mura and the twins. However, as soon as Mura is found, she disappears on one of her manic episodes and is discovered up a tree where she spots an enigmatic monolith. This sighting instigates an exploration of an ancient and dangerous mystery. By unravelling a series of puzzles, the intrepid explorers uncover a vanished civilization but, in so doing, they also unwittingly unleash a primordial horror which threatens to destroy not only themselves, but their entire world.