Miri Gill has some problems.
First problem: she's the middle kid between two sets of twins.
Second problem: she's just walloped one of her older brothers on the head with a shovel and has been sent to her room, probably for the rest of her life.
Third problem: Her family has moved to an old house in the country, and her new room has the ugliest wallpaper in the world.
Fourth problem: Miri sees a little piece of glass taped to her ugly wall and decides to take a peek through it.
Fifth problem: Suddenly, she's not in her bedroom anymore.
Sixth problem: Her problems are just beginning.
. . . the door opened soundlessly and a girl about her own age slipped quickly inside. She closed the door behind her and made a flying leap into the closet. There was a moment of complete silence, during which Miri pondered what on earth she should do, and then a pair of large gray eyes peered around the edge of the closet door.
"Oh my gosh!" said the girl in a whisper. "You're here."
Now Miri finds herself face to face with Molly, a girl who insists that the room is hers, that the year is 1935, and that Miri has come to save her. And, after she has a brush with Molly's cousin Horst, Miri has to agree—Molly does need saving. But how?
Together, the two girls set out to overcome the perils of lost treasure, bad eyesight, and time itself, and in the process Miri and Molly learn that magic is just a way of setting things right.