12-year-old Maggie Morris, a creative and outspoken writer, has a dilemma. Her mom left two years ago, leaving behind a dad to raise two daughters and hundreds of painful questions. Mystery and secrets surround her parents' divorce, and the weirdest thing is, Maggie can't remember everything about it. It's as if the details have been locked behind a door; there are pieces still floating around in her brain like tiny scraps of paper and unrelated, fuzzy pictures.

With infinite doubt swirling inside, Maggie retreats to her journal, creating a story about a dangerous outlaw on the run in the backwoods of Saturn's uninhabited rings. Her main character, Willy, is a crotchety, bearded cowboy from planet Earth on a mission to save his prize-winning pig. Brave, brawny, and in his prime, there is nothing Willy can't do. Yet, even with Willy by her side, Maggie can't stave off the unrelenting feeling of encroaching darkness. Like a growing shadow in the corner, bigger and bigger, her monster becomes.

Will the darkness eventually overcome her?

Will she solve the mystery behind her mother's abandonment?

Will Willy ever rescue Opal?

And what is a puka shell?