Episode Title:Tortuga Tune-up.Episode Description:Aviva is troubled—by the Tortuga. She realizes that she's never programmed one of her favourite inventions with the ability to swim underwater. Searching for inspiration, the Kratt bros go underwater to explore a coral reef where they find a hawksbill sea turtle. While gathering information for Aviva, the bros learn all about sea turtle shield defence, as their new animal friend fends off a hungry tiger shark. Just when everything seems okay and the Tortuga is ready to test its new abilities, the master key is lost and sinks to the bottom of the ocean. The bros must then use sea turtle powers to fend off the circling shark and recover the key.