Magic by the Lake

Our four children head to the lake for the summer, and what do they find there? Ah, more magic! This time the magic arrives in the form of a turtle who can tap into the magic of the lake. The magic needs to be watery magic, and the kids go wrong a few times there. But they manage to have some lovely adventures. And there is the huge problem of their new step-dad's struggling bookstore...Could the magic possibly help with that?