Special episode of the animated deep sea adventure series. Join Captain Barnacles and his intrepid band of explorers, The Octonauts, for more deep sea adventures. The Octonauts roam the oceans in search of adventure and fun. Whether it's a perilous voyage to the bottom of the sea or the piratey pursuit of a giant squid, the Octonauts leap into action and always prove that eight heads are better than one.

Returning home from a mission along an African river, the Octonauts encounter a gang of large, territorial hippos.