Kate Humble joins a team of geologists on an awe-inspiring adventure to Ambrym in the Vanuatu island chain. Here, she undertakes an arduous journey to Marum - a volcano containing one of only five lava lakes on the planet - abseiling right to its heart to discover if another major eruption might be imminent. Along the way, she discovers how the volcano has shaped the customs and traditions of the islanders and discovers what it really means to live each day on the slopes of an erupting volcano.