At Greenglass House, the innkeepers' adopted son Milo plans to spend his winter holidays relaxing, but soon guests are arriving with strange stories about the house, sending Milo and Meddy, the cook's daughter, on an adventure.

Twelve-year-old Franny Whitekraft lives quietly with her adopted parents on a farm on Vancouver Island until the spring of 1945 when the three Madden children move in, UFOs and ghosts appear, and an important military airplane disappears.

After thirteen-year-old Hattie Oh casts a dangerous spell so her adopted sister, Riley, will get a share of her inherited magic, Riley must undertake a near-impossible quest to save Hattie from death.

"Twelve-year-old Milo is stuck spending the winter holidays in a house full of strange guests who are not what they seem--again! He will have to work with friends old and new to uncover clues in search of a mysterious map and a famous smuggler's lost haul"--