The Water Castle (2013) by Megan Frazer Blakemore is a tale with classic themes. It takes place in a small Maine town known as Crystal Springs, a place that isn’t on any map. When young Ephraim’s father suffers a stroke, his mother takes the family to her childhood home, the Appledore family estate, hoping her husband will recover there.
As Ephraim tries to fit in at the local school, and adjust to life at the unusual stone house that was formerly a resort known for the curative properties of its waters, he discovers the existence of a Fountain of Youth legend. Together with classmate Mallory, whose family has taken care of the estate for a century, they pick up where their ancestors left off and try to solve its mystery in the hopes of saving Ephraim’s father.
This mystery for middle grade students (and anyone else who enjoys a good story) sounds charming.