Fiona Bruce and Philip Mould investigate a lovely landscape painting, purported to be by one of the forefathers of impressionism and one of the most important artists of the 19th century, Jean-Baptiste-Camille Corot. Its owner, Sally Green's late husband, bought it in the late 70s, primarily for the impressive frame. He was always intrigued by the painting and wondered if it was genuine. Sally is now on a mission to finish what he started. However, the painting was turned down by the authority on Corot, so the team will have to find new evidence to help persuade them to change their mind. A lot is at stake. If the work is genuine, it could be worth £70,000. If not, just a few hundred. Sally has noticed in her late husband Derek's papers that the painting was once owned by a prominent Scottish art dealer, Sir John Reid. She has a book which shows that he also owned other works listed as by Corot. As Fiona and Philip draw up a provenance list of previous owners, his is the first name they need to investigate. But there are also a number of other intriguing stamps and labels on the back of the picture that will need to be followed up. Sally believes in the painting, and her husband's legacy is counting on their research. Philip opens the investigation by heading to the renowned Wallace Collection in London to refamiliarise himself with works known to be by Corot. He also examines Sally's painting forensically. Under the microscope, it's clear that the painting was put together in an idiosyncratic manner. On close inspection, the back of the painting also shows a new provenance lead. Professor Aviva Burnstock at the Courtauld Institute in London thinks that they might be able to trace the actual canvas it's been painted on. Can the latest scientific analysis help the team get to the bottom of who actually painted it? Meanwhile, Fiona delves into the history of the painting. The journey takes her from Scotland to France, where she discovers the extent to which Corot was faked. She meets Claire LeBeau, the descendent of Pierre Dieterle and the expert who has the final say on whether Sally's picture will be counted as a genuine work. Fiona and Sally spend a nervous moment looking through a giant book of fake Corots, seeing if they can spot her painting. Can Philip get some positive news from the technical analysis? Once all the evidence is gathered, have the team done enough to convince the world's leading authority on Corot that Sally's painting really does belong in the catalogue of the artist's work?