Can you solve the sea monster riddle?

According to legend, once every thousand years a host of sea monsters emerges from the depths to demand tribute from the floating city of Atlantartica. As the ruler of the city, you'd always dismissed the stories... until today, when they rose out of the roiling waters, surrounded your city and demanded a ransom of pearls. Can you figure out which chest of pearls is the ransom? Dan Finkel shows how. [Directed by Artrake Studio, narrated by Addison Anderson].