Kwazii: Captain For a Day! is the 37th episode of Season 1.
When Captain Barnacles catches a cold and starts sneezing and coughing, he asks Kwazii to be in charge of being the captain while he rests, but Kwazii learns that being the captain of the Octonauts is not always easy than he thinks.
The episode starts with Captain Barnacles walking in the hallway rubbing his nose which seems to be dripping and sniffs the snot back in. Just then Kwazii comes out of the Octo-Hatch with his helmet and pads on and holding his skateboard. He asks if the captain is ready to go to a carnival with their friends but Barnacles just coughs a yes and goes back to his room to grab his roller skates and safety pads and helmet. With a confused look on his face, Kwazii heads to the Launch Bay to meet Peso who is waiting for him and Captain Barnacles. Later, Jake, Izzy, Cubby, Skully and the three Octonauts spin their wheels to the carnival when suddenly Captain Barnacles sneezes and crashes into a rose bush. The friends roll over to him and Peso and Kwazii decide to take him to the Sick Bay in the Octopod. After taking the captain's temperature, Peso discovers that Barnacles has a fever so he tells him that he needs to drink warm liquids and go to bed, but Captain Barnacles, struggling to get up, asks who will be the new captain while he rest. So without further or do, Kwazii steps in to volunteer to be the new captain for a day.
Captain Barnacles: (sneezes and crashes into a rosebush) Whoaaa! Oof!
Kwazii: Oh no! Captain!
Peso: Flappity Flippers!
(Everyone turns and skates to the captain)
Jake: Captain Barnacles! Are you okay?