Los Diamantes de la Gran Duquesa (English: The Grand Duchess's Diamonds) is a 1972 comic written and drawn by Francisco Ibañez for the Mortadelo y Filemón (Mort & Phil) comic series.
entrusts Mortadelo and Filemon with the task of guarding the Duchess' personal treasure: Ten diamonds of enormous size.
But as they arrive at the hotel, one of Mortadelo's usual mishaps with the diamonds piques the interest of the crook Vicente el Urraco, who promptly steals the invaluable gems.
El Urraco hides the diamonds in ten separate locations all around the city: An apartment building, a construction site, the harbor bay, the sewer, a farm, the top of an alley tree, a park, a barber's salon, a practical jokers' clubhouse, and a crook's flat.
As a result, they end up being chased by both their boss and the Duchess, who suspect them of having stolen the diamonds.