At the school, Roisin’s juice has turned one of her teeth blue. The children talk about brushing your teeth and the young Roisin boasts that she never does. Although the other children try to explain the importance of keeping your teeth clean, Roisin just doesn’t get it. They decide to hike to Whale Cove where they meet Finn Whale, a species of whale commonly found off the coasts of Ireland. He’s a lonely mammal with a bad case of bad breath. Through a lively song, the children help Finn clean his teeth and rid himself of his unsocial breath. The young Roisin learns the importance of good dental hygiene.