Seventeen-year-old Riggle is living in rural Indiana with his uncle and uncle’s girlfriend after the death of his parents. Now his uncle is missing, probably on a drug binge. It’s Monday, and $800 in rent is due Friday. Riggle, who’s been suspended from school, has to either find his uncle or get the money together himself. His mission exposes him to a motley group of Opioid locals --- encounters by turns perplexing, harrowing and heartening.

It started with a single child and quickly spread: you could get high by drinking your own shadow. At night, artificial lights were destroyed so that addicts could sip shadow in the pure glow of the moon. Gangs of shadow addicts chased down children on playgrounds and rounded up old ladies from retirement homes. Cities were destroyed and governments fell. One hundred fifty years later, Mira, her shadow-addicted friend Murk, and an ex-domer named Bale search for a possible mythological cure to the shadow sickness --- but they must do so before the return of Halley’s Comet, which is only days away.