As a child, Chris Thorogood dreamed of seeing the rare and endangered, parasitic plant Rafflesia - the plant with the world's largest flowers. Today he is a botanist at the University of Oxford's Botanic Garden and has dedicated his life to studying the biology of such extraordinary plants, working alongside botanists and foresters in Southeast Asia to document these huge, mysterious blooms. Pathless Forest is the story of his journey to study and protect this remarkable plant - a biological enigma, still little understood, which invades vines as a leafless parasite and steals its food from them. We join him on a mind-bending adventure, as he faces a seemingly impenetrable barrier of weird, wonderful and sometimes fearsome flora; finds himself smacking off leeches, hanging off vines, wading through rivers; and following indigenous tribes into remote, untrodden rainforests in search of Rafflesia's ghostly, foul-smelling blooms, more than a metre across. And to see if Rafflesia itself can be saved.