Cee has been trapped on an abandoned island for three years without any recollection of how she arrived, or memories from her life prior. All she knows is that somewhere out there, beyond the horizon, she has a sister named Kay, and it's up to Cee to cross the ocean and find her.

In a world apart, 16-year-old STEM prodigy Kasey Mizuhara lives in an eco-city built for people who protected the planet?and now need protecting from it. With natural disasters on the rise due to climate change, eco-cities provide clean air, water, and shelter. Their residents, in exchange, must spend at least a third of their time in stasis pods, conducting business virtually whenever possible to reduce their environmental footprint. While Kasey, an introvert and loner, doesn't mind the lifestyle, her sister Celia hated it. Popular and lovable, Celia much preferred the outside world. But no one could have predicted that Celia would take a boat out to sea, never to return.

Now it's been three months since Celia's disappearance, and Kasey has given up hope. Logic says that her sister must be dead. But nevertheless, she decides to retrace Celia's last steps. Where they'll lead her, she does not know. Her sister was full of secrets. But Kasey has a secret of her own.