In ancient Rome the slaves are revolting ... and not only that, they've stolen Julius Caesar's own galley, the finest warship in the Roman navy. Under their heroic leader Spartakis, the former galley slaves make for the little Gaulish village where Julius Caesar's old enemies Asterix and Obelix live - only to find the place in crisis, for Obelix, after drinking the druid Getafix's magic potions on the sly, is first turned to stone and then reverts to childhood. In search of a cure for him Asterix, Getafix and their new friends the galley slaves sail to the wonderful continent of Atlantis, ruled by its high priest Absolutlifabulos - and the ensuing sea battles against the Roman navy are fast and furious ...