After the sudden and mysterious death of her mothers, 12-year-old Alex Perkins flees from the orphanage upon discovering a godmother, Mimi, mentioned on the back of a family photo, which turns out to be a postcard addressed to her. That address leads her to the In Memoriam real estate agency in the town of Medio Camino, but to her surprise, she discovers that… Mimi is a ghost and that ghosts exist!