When the tide recedes at this point on the Severn estuary, rare evidence of stone age activity is uncovered. Time Team are on a three-day mission to help recover some of these relics before they are washed away. It involves excavating and painstakingly examining 15 cubic metres of muddy silt; but time is against them. The Mesolithic period is poorly understood, because these people were highly mobile hunter-gatherers who did not build permanent structures. They uncover some of the smallest artefacts they have ever handled. Phil and Brigid are fascinated by ancient footprints of adults and children, preserved in the sand. Phil excavates the massive tooth of an aurochs, an extinct giant prey animal. They are joined by Martin Bell of Reading University, Mesolithic specialists Nick Barton and Robin Crompton, and food expert Jacqui Wilson who cooks up a stone age feast.