Of all the poor people living in "the willies"—the foothills of the mountains of West Virginia—the Casteels were considered lowest. Yet, the eldest daughter, Heaven Leigh Casteel, was still the prettiest and smartest girl in the backwoods, despite her ragged clothes and dirty face. Heaven encouraged her four younger siblings to cling to their pride and hope for a day that they'd escape their poverty and show the world what decent, talented children they were. But when Heaven's stepmother runs away, Luke, her irresponsible drunkard of a father, decides to give away his children one by one, tearing her family apart. Heaven is sent off to live in the home of Luke's deranged ex-lover, Kitty. There, she is subjected to more torment but finds solace in the arms of her stepfather Cal, as they begin a taboo relationship.

Dark Angel picks up directly after Heaven finds a new life in her estranged grandmother and grandfather, Jillian and Tony Tatterton's exquisite Boston mansion, Farthinggale Manor. But even in the world of the wealthy, there are strange forebodings, secrets best forgotten. As Heaven reaches out for love, she is slowly ensnared in a sinister web of cruel deceits.

Heaven, now happily married, is ready to settle back in her hometown. But after a trip to Farthinggale Manor, Heaven is persuaded to stay. Lured by her grandfather Tony Tatterton to live amidst the wealthy and privileged Heaven seems to have it all until the ghosts of her past rise up once more, threatening her precious new life.

Heaven's daughter Annie finds herself orphaned and crippled. Whisked off to Farthinggale Manor by Tony Tatterton, Annie pines for her lost family, especially for her half-brother Luke. Without the warm glow of Luke's love, she is lost in the shadows of despair and forced into submission by Nurse Broadfield. When Annie discovers a cottage hidden in Farthinggale's woods, the mystery of her past deepens. Even as she yearns to see Luke again, her hopes and dreams are darkened by the sinister Casteel spell.

The mysteries of the family are finally unlocked. Heaven's mother Leigh had to escape from Farthinggale Manor and the secrets she harbored. Falling into the arms of Luke Casteel Sr., his devotion promised her hope as only Luke knew her deepest of secrets. Bravely she bore the suspicions of the hill folk, as she tried to grasp the happiness that long eluded her. With a baby girl, Heaven, on the way, she hoped for a chance at happy ever after.