The Kratts are studying great white sharks while, Chef Gourmand is looking for ingredients for shark fin soup. Later, when Martin knocks the Creature Power Suits into a deep Arctic trench, the brothers search for them in the brand-new Octopod submarine. Then Aviva takes the lead when she wants to upgrade the Tortuga with swimming capabilities. Finally, the team is on a mission to decode the secret language of dolphins using a new invention.