Her family travels to dimensions using doors only they can see. But the key to saving those hidden worlds and her missing aunt lies in a childhood summer she can't remember and a power she didn't know she had.

Kate shouldn't be here. Yet here she was, risking her mom's wrath, to come back to a house she can't remember. A house her estranged aunt lived in until her disappearance a year ago. A house her mom desperately tries to keep Kate from.

But Kate can't resist the pull of the house as it draws her in and soon memories of a forgotten magical childhood summer spent with her aunt start to surface.

Seeking answers, Kate discovers her aunt's hidden journal, locked away. Not sure what to expect, she begins to read and is soon lost in her aunt's tales of her adventures and danger on other worlds. She also learns her family comes from a long line of travelers and can travel to other dimensions through doors only they can see.

When a powerful creature thunders down from a hole ripped in the sky and threatens Kate, she is left shaken with the possibility that her aunt may be alive, held captive for information in the journal that could end all worlds and Kate is the key to finding her.

But first she must figure out how to see those doors...