Under the Mountain Overview

Rachel and Theo are no ordinary twins: they have the ability to communicate telepathically, which gives them a unique bond. However, following the sudden death of their mother, this bond begins to weaken. When they are sent to live with their aunt, uncle and cousin Ricky in Auckland, a rift begins to form between the twins, with Theo rebuffing all of Rachel's attempts to confront their grief.

Meanwhile, Rachel becomes intrigued by the abandoned Wilberforce house across the lake from their aunt and uncle's place, and despite Ricky's warnings, she manages to convince Theo to join her on an investigation. What they find inside the house is deeply strange, and the creatures who live there much creepier than imagined. But the meaning of their discovery only becomes clear when they meet the mysterious Mr. Jones, who explains that the creatures are guardians of an ancient evil that will soon awaken and destroy the world. Moreover, Rachel and Theo have the telepathic gift to defeat the evil, but their success depends on their ability to work together and the strength of their connection. Theo, however, would prefer to combat the menace alone.