Dara O Briain begins with a mission to uncover the inner workings of volcanoes. His journey starts in Sicily, home to the mighty Mount Etna - Europe's largest and most active volcano.Ascending Etna's slopes, Dara confronts an alien landscape of hardened lava, still venting hot gases from deep beneath the Earth's crust. Near the smouldering summit, he meets volcanologist Dr Emanuela De Beni, who's dedicated her life to understanding this volatile giant. She explains how seismic sensors, drones, and thermal imaging are used to predict eruptions. A few hours' warning is all they might get! He also meets Dr Daniele Andronico, who studies the aftermath of each eruption in a bid to keep the nearby city of Catania safe and moving.On his descent, Dara discovers lava tubes, underground tunnels carved by molten rock. He meets scientist Dr Sonia Calvari, who reveals the hidden dangers these formations pose to communities living above them.But volcanoes aren't just destroyers - their power nurtures extraordinary gifts. Dara explores how volcanic soil supports thriving vineyards that produce some of the world's finest wines. Vintners Steph and Ciro demonstrate how their crops benefit from the unique environment, even as ashfall from Etna's regular eruptions challenges their daily life.The episode's climax takes Dara on a voyage across the Tyrrhenian Sea to the island of Stromboli, a volcano so active it has earned the nickname ‘Lighthouse of the Mediterranean'. After a steep climb, Dara reaches a viewing platform to witness Stromboli's spectacular eruptions, with fiery lava illuminating the night sky.