Pavonine, Mayhap, and Winnow Ballastian were three, five, and seven when their parents disappeared, leaving them alone in Straygarden Place, a house surrounded by tall silver grass. Their parents left a note: “Do not leave the house. Do not go into the grass. Wait for us. Sleep darkly." For the last seven years, they've stayed and waited while the house took care of them and their droomhunds slipped into their minds at night to help them sleep. Now, though, something is wrong with fourteen-year-old Winnow, and it's up to twelve-year-old middle-sister Mayhap to unravel the secrets of their home and save her family.