Fiona Bruce and Philip Mould investigate a charming little white flower picture, purported to be by one of the most important abstract artists of the 20th century, Piet Mondrian. Its owner, American Jeffrey Kroll inherited the picture from his mother and believes it to be genuine. However, the painting was turned down by the authentication committee, 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 over £250,000. If not, just a few hundred. Jeffrey has spotted that it sold at a major auction house in 1993, listed as a genuine work by Mondrian, entitled the White Chrysanthemum. It has a whole range of intriguing and genuine-looking labels on the back, showing what appears to be a solid and traceable history. However it wasn't included in the 1998 catalogue raisonne of genuine works by Mondrian. Despite this, Jeffrey still believes it is the real deal. But as the team know all too well, opening up an old case to find new evidence is never simple. Philip opens the investigation by heading out to the Netherlands to get to know the lesser known side of Mondrian's work — his flower pictures. He also examines it forensically. Under the microscope, it's clear that the paper was made at the same time as Mondrian was working — so there are positive signs early on. On close inspection the back of the painting also shows a new provenance lead. Armed with further evidence he takes it to Professor Aviva Burnstock at the Courtauld Institute in London for more testing. Can the latest scientific analysis help earn the picture a place in a future catalogue raisonne? Meanwhile Fiona delves into the history of the painting, its provenance. The labels on the back also lead her to the Netherlands, where she in worryingly unable to identify it in any of the stockbooks of the galleries and dealers which it purportedly passed through. On discovering that there is no known trace of one of the most recent owners listed in the 1993 auction house sale, a Jacob and Jan de Groat in Arizona, Fiona discovers some more disturbing evidence which leads her to consult with retired art detective Dick Ellis. Ellis arrested many art forgers in the 1990s, could he find damning proof against Jeffrey's picture? Once all the evidence is gathered, have the team done enough to convince the world's leading authority on Mondrian, Wietse Coppes, that Jeffrey's painting really does belong in the catalogue of Mondrian's work?