The 19 year restoration of Leonardo da Vinci’s Last Supper fresco has revealed that only 20% of the original painting is still visisble. Will we never be able to see what the original painting looked like? In this thriller-like quest, a bestselling author and historian goes in search of a mysterious second version of the famous ‘Last Supper’ fresco, reportedly painted by Leonardo da Vinci and his workshop for the King of France, Louis XII.