Pearl is the biggest mystery Peter has ever known. She's beautiful, she's quiet...and she might be an alien. Pearl and her brother Axel seem like runaways at first. They're hiding in the Pennsylvania woods, afraid of being discovered. Axel explains to Peter that they don't belong on Earth - they're stranded. They belong on Enceladus, a tiny moon of Saturn, and they want to go back home. It seems believable, but is a vibe coming from Axel that Peter doesn't like. As soon as Peter gets a chance, he turns to run away. But everything changes when Pearl silently asks him to take her with him. Without another soul knowing, Peter hides Pearl in his bedroom. She refuses to speak, but they gradually form a bond and become closer. The lines between make-believe and reality blur as Peter finds himself falling for this beautiful girl that might be from another world. But Axel is still out there, and he wants his sister back. Peter vows to give his life to protect her, but will it be enough?