The Lost Van Gogh begins when Vincent van Gogh's Portrait of Monsieur Trabuc suddenly turns up at the Metropolitan Museum of Art - a $50 million painting shipped from Argentina like an ordinary package via UPS. The case goes to Clay Ryder, the NYPD Major Case Squad detective assigned to art theft.
Ryder discovers a claim filed in Paris in late 1944 by a widow, accusing a German officer of stealing the painting. But the officer, notorious for his cruelty as an SS interrogator, died in a car crash in Germany at the war's end, and the whereabouts of the Trabuc for all the years in between remain a mystery. Ryder's investigation brings him to the only heir, Rachel Meredith, who teaches at NYU. The museum presents the painting to her in a spectacular PR coup, hyped as a Holocaust art theft with a happy ending, and it winds up on the front page of newspapers around the world.
It's a closed case for Ryder, but he's still intrigued by who sent the Trabuc from Argentina. One of his most reliable contacts in the art world floats a theory that ties the Van Gogh portrait to a black market auction in the 70's that might have involved a Swiss art dealer and an international crime kingpin with unlimited cash. Ryder is irrevocably pulled back into the Trabuc puzzle when Israel's Mossad pays him a clandestine visit; the news splash about the Trabuc is the only link they've had to the SS officer in decades.
Meanwhile, art dealers, auction houses, and museums vie with one another to buy the Van Gogh from Rachel Meredith. When she refuses to sell her legacy, the situation goes from predatory to violent. Ryder has to race against time to outmaneuver a cunning mastermind who will resort to as many murders as it takes to get hold of the Trabuc.