Kate Humble joins a team of geologists on a journey right to the heart of one of the most active volcanoes in the world. On the island of Tanna in the Vanuatu archipelago lies Yasur - a volcano that erupts constantly, firing out red-hot lava bombs and showering the island in thick black ash. To discover whether another devastating eruption might happen, the team needs to collect a lava bomb the minute it is hurled from the crater. As they prepare for their death-defying mission, Kate explores the island and discovers how the volcano shapes the lives, traditions and beliefs of everyone who lives in its shadow.