Fiona Bruce and Philip Mould must prove that a sketchbook is the work of a young Toulouse-Lautrec, overturning a decision made by a committee of experts on the artist. The drawings in the book are of a very different subject matter to Lautrec's famous works, and are dated to when he was a teenager - a period of his life that is largely a mystery. To get to the truth, Fiona and Philip travel to the town in the south of France where Lautrec grew up and visit the grand family home where he spent much of his youth.