Maggie and Jamison, a teenage sister and brother, are unwillingly drawn into amysterious world of magic in the small West Texas town of Fort Richards.Their everyday lives were normal-until one Saturday in October, when a freakywoman dressed in black stepped off the bus and entered their mom's hotel. Thewoman introduced herself as Mrs. Johnson, but Maggie quickly discovers herreal name is Vivienne, and she's not who she claims to be. Vivienne reveals thatMaggie is a changeling, and that she is Maggie's true mother. Vivienne has come totake Maggie home -with her!Maggie is betrayed by someone she trusted, and is taken by Vivienne throughThe Imaginaerium Engine into the shadowy Otherworlds, to live with her.Maggie insists she'll escape, but breaking free from webs of mystery and magicisn't easy. As Vivienne leads Maggie through the Otherworlds, she meets allieslike the trickster Abarta and beautiful Queen Niamh. But as Maggie's powersbegin to emerge, she has a disturbing vision of a looming disaster in theOtherworlds, orchestrated by the malevolent Fomoire. They're after theImaginaerium Engine, which would give them the power to destroy her familyand the world. Now, plans for escape are set aside as Maggie must figure outhow to save them all within the week.... even though she has no idea what she's doing!