HOUSTON’S WHITEBEAM follows climber, botanist and poet Libby Houston who, at 80 years old, continues her work climbing the 300-foot cliffs of Bristol's Avon Gorge to investigate rare plants. By reaching every ledge on every rock face and using her poet's eye for close observation, Libby has helped establish the area as one of England’s most important botanical sites. But as it stands, there is only one known member of her namesake discovery - Houston’s Whitebeam - and reflecting on its inevitable extinction prompts Libby to contemplate her own legacy.