In an ordinary town, on Fletcher Street, which you probably have in your town as well, there is a very special house, where Mr. Froggy, Karenna, Simon, and Lion live. The friends are very excited: the mysterious sulx, a legendary creature, is somewhere close. They find a nest, some feathers and paw prints, which belong to the sulx. Why is she here? And is it true that the sulx is stealing little kids from their parents? Together, with the magical, shape-shifting submarine, known as Fire Opal, and with the help of a little miniature yellow unicorn, known as Lemon, the mysterious sulx is revealed. Now the friends are on a mission to share their experiences with the sulx to each other.