The story of the island of Ireland's epic geological journey, spanning 1.8 billion years.In this first episode, we reveal how two ancient continents swallowed an ocean as they slowly approached each other over millions of years. The collision point would eventually become Ireland, and we show how the battle scar from this immense fusion runs like a suture in the rock from the Shannon Estuary in County Limerick to Clogherhead in County Louth. This merging and folding of lands took millions of years, and, even after this ancient coming together, the island's story had only just begun. As the rocks continued to move very slowly north, we explore how changing sea levels submerged Ireland in shallow tropical waters, creating the limestone deposits that dominate our landscape and are exposed so impressively at The Burren in County Clare.We examine evidence for Ireland's long-lost deserts that formed as the island crossed the equator past present-day Egypt. In Newfoundland, the rocks reveal the legacy of the colossal forces that slowly ripped Ireland from North America over millions of years, and, on the Antrim coast, we investigate the volcanic hotspots that created the iconic Giant's Causeway around 60 million years ago.