When Earl sings a sea shanty about a sunken treasure ship at the bottom of Lake Lucky, Penny becomes convinced that it’s true. Penny wants to put together an underwater exploration but the Hoppers, led by Filipa, are dubious about the authenticity of the tale. Through research, Penny convinces the Hoppers that it there’s a good chance it is true, but they need Lonny Beaver’s mini-submarine to see for themselves. Penny and Filipa wind up on a thrilling underwater adventure, and discover that there is treasure down there – but it’s not at all what they imagined.

Follows a diverse group of best friends who encourage young children to embrace their individuality. Hop, an energetic, sympathetic frog with one leg shorter than the other, guides his endearing and eccentric group of friends in solving kid-friendly situations.