ranjit started reading Magic by the lake by Edward Eager
On a vacation, four children find themselves with an entire lake full of magic, which …
An AI book recommender (en.app) confidently identified this as a dimly-remembered book from my childhood, pointing out the specific details from my request that exactly matched this book. None of those details actually occur in this book at all, but it is a pretty fun read and I might check out the others in the series.