The Octonauts' floating temperature sensors alert them to a risk of waterspouts due to a rise in sea surface temperature so they decide to retrieve the devices for safe-keeping. But Kwazii gets into an argument with a possessive triggerfish which has adopted one of the devices as its home, and they both get carried away by a waterspout. Kwazii ends up having to defend the fish from a seabird and a swordfish that want to eat it. Luckily the characteristic grunting sounds that triggerfish make when distressed enables the other Octonauts to locate them.