The Night Gardener, by Jonathan Auxier
After being separated from their parents by a shipwreck, Molly and Kip travel to the spooky “sour woods” to work for the Windsor family. The branches and roots of a huge tree grow through the walls and ceilings of the house.
Each morning, Molly cleans muddy shoe prints off the floors and sweeps leaves from the hallways. Molly and Kip discover that these are left by a mysterious man who comes to the house every night to tend the tree.
Molly and Kip notice other distressing things. Each night, everyone in the house suffers from terrible nightmares that are connected to the Night Gardener’s visits. And each morning, Mr. and Mrs. Windsor and their children are sicker and more despondent. Even Molly, who sleeps in the house, is affected as her red hair and green eyes turn black.
The logical thing would be for them all to leave, but the tree holds them by giving each of them the one thing they most desire. Can Molly and Kip find a way to break the spell and save the Windsors before it’s too late?