Rural East Texas, 1968 Calvina ("Cal") Jean Prather is a 10-year-old precocious angel hunter living in Onward, Texas. She is blessed by birthright to be a "special purpose" child who can see the angels on Earth as they go about their celestial tasks. She lives with her mortician granddaddy in their combined house and funeral parlor. Cal's best friend is Moody, a child with social challenges. Enthralled by local legend, the duo secretly heads for the forbidden reaches of the Sabine River Bottom, where they witness a murder confession while playing an innocent game of Indian scouts. When the killers seek to silence Cal and Moody as witnesses, the children realize that they are tangled in a dangerous web. Cal must soon choose between her solemn oath not to call on the angels to intervene in Earthly matters, or risk the lives of those she loves. Only one angel can be summoned on such short notice who has the light and power to save her: Lucifer. Her gamble with the devil brings her to the jaws of death, and Onward to a reckoning with their own prejudices. Cal must choose between her promise, her loved ones, and her own place in eternity. The revelations reveal the circumstances of her mother's death, the origin of her powers, and who she can claim as her father.