The story so far: Giovanni Bellini, one of the great artists and teachers of the Italian Renaissance, was asked to contribute to a series of bacchanal canvases commisioned in 1514 by Venetian duke Alfons d'Este for display in his palace chambers. Bellini's contribution -- a sort of Olympian slumber-party scene, featuring lecherous Priapus ogling nubile Lotus -- was largely completed by the time of the artist's death in 1516.

Flash forward to the mid-20th century, as restoration experts at Washington's National Gallery of Art, which acquired The Feast of the Gods in 1942, begin cleaning up their Renaissance masterpiece. They discover their "Bellini" is not what it appears to be -- that significant portions were altered and repainted sometime shortly after the master's death. Who would have dared tamper with the great man's work? And why?