In a single brief childhood scene set in Liverpool, England, 1760, Angelique's early interest in Barnabas is established. The young Angelique, around 10 years of age, is portrayed by actress Raffey Cassidy. She is depicted with her mother, a servant, departing on a sailing ship from the Liverpool docks for "the New World," along with the Collins family. The childhood scene also helps establish Angelique's class-based resentment of the Collins clan's privileges, for she is cautioned by her mother that she must accept her place, servitude, in the social structure of the time and not even gaze freely upon her "betters," including Barnabas.
As she develops into an attractive, dark-haired young woman, Angelique seems to follow in her mother's footsteps as a servant to the Collins family in their New World mansion, Collinwood. However, she develops skills in witchcraft and - whether through natural or magical charms - arouses the amorous interest of the Collins heir, Barnabas. Though he clearly experiences carnal pleasure with her, when Angelique asks him to affirm love for her, Barnabas candidly rejects the notion. Instead, he falls in love with a young woman closer to his own social standing, Josette duPres.
Relegated by the prevailing attitudes of the era to scrubbing the Collins floors while the man she had hoped would love her openly romances another of her "betters," Angelique sees Barnabas and Josette tenderly embracing. Driven by romantic and class jealousy, she begins to use the dark empowerment that witchcraft has provided her to wreak revenge upon Barnabas and the Collins family, and to improve her own fortunes.
Angelique then commits the two pivotal acts of vengeance that drive the subsequent action of the film: She causes the death of Josette, who is spellbound and compelled to leap from Widow's Hill; and she places the curse of vampirism upon Barnabas. (While playing a similar role in the plot to events of the original daytime serial, the film depiction has the sequence reversed, with Josette magically induced to kill herself before Barnabas' vampire curse is evident; in the original series, Josette flees from Barnabas and hurls herself from the cliff in horror upon discovering that Barnabas has become a fanged bloodsucker as a result of Angelique's curse.)
According to the later recounting of "legends" by Elizabeth Collins Stoddard, Barnabas tried to persuade the people of Collinsport that Angelique has placed him under a curse, but they found him deranged. However, the film shows the actual events in 1776, when Angelique herself leads the townspeople in a torch-carrying mob to Collinwood, points out Barnabas, declaring "There's the monster!" and facilitates his imprisonment in a buried coffin for almost two centuries, until 1972 when the film's principal events are set. The townspeople appear to harbor no suspicion of Angelique's being a practitioner of black magic or of her responsibility for Barnabas' transformation into a killer.
Over the ensuing years, the Collins family fortunes decline. (Apparently there were heirs other than Barnabas, for both Collinwood and the family fishing business endure, though both decline into near-ruin.) Angelique, adopting a series of guises through the decades to conceal her true age, establishes a prosperous rival to the Collins fishing business that she calls Angel Bay Seafood and becomes a well-known and at least superficially highly regarded pillar of the community of Collinsport. As the film reaches the events of 1972, Angelique is shown to have changed her naturally dark hair color to blonde and now goes by the name "Angie" Bouchard.
While her principal villainy in the film is supernatural hostility against the Collins family, Angie is also depicted as having more generic qualities intended to turn audiences against her. She is a rather callous businesswoman who enjoys imperiously giving orders, demands unrealistic productivity from her workers, and is indifferent to others' suffering. ("Accidents happen," she shrugs when initially told a group of several workmen have been killed the night before, uninterested until she learns that their throats were torn out at the same location where she'd presided over Barnabas' burial 196 years before.) She is also depicted as a bit vain, driving through town in a flashy red convertible sportscar, smiling and waving at the townspeople, and checking herself in the mirror. She hypocritically characterizes the original Collins family as "looking down their noses" at others, while later proclaiming herself (and Barnabas, for whom she still carries a determined torch) better than the other townspeople. She declares herself the "last big fish" in the "little pond" of Collinsport, looks down upon other people by comparing them to ants she can crush, and attempts to compel Barnabas to "rule" the town alongside her.
Over the course of the film, Angie confronts the escaped Barnabas and attempts anew to seduce him (succeeding once in a tumultuous scene of lovemaking), both threatening him and offering him a "business proposition" to rule Collinsport with him in a sort of "marriage of monsters." Eventually - spurned again - she uses magical means and, assisted by her cowed or entranced Angel Bay board members, easily imprisons Barnabas again in a chained coffin. She also casts a spell -- "Sleeping flame / I summon thee / To your form return / Make the night as bright as day / And burn, baby, burn!" -- to cause a catastrophic explosion at the refurbished Collins family fish cannery, relegating the rival business (which Barnabas had briefly revitalized) to the state of ruin to which she had previously reduced it.
After Barnabas' escape, in a climactic supernatural battle at Collinwood, Angelique has what appears to be a final confrontation with the remaining Collins family members. During these scenes, it is revealed that Angelique has cursed not only Barnabas, but also 15-year-old Collins heiress Carolyn Stoddard, who was bitten in infancy by a werewolf and is now a werewolf herself. She also confirms to the family her role in killing Barnabas' parents (the film audience has already seen this during the opening scenes), and reveals that she is also responsible for the death of Laura Collins in a supernatural "boating accident," and thus has also caused psychiatric issues for young David Collins due to his contacts with the spirit of his mother Laura.
Although Angelique's magical abilities allow her to prevail initially in the violent final conflict with Barnabas, shotgun-wielding Elizabeth Collins Stoddard, and transformed werewolf Carolyn Stoddard, she is ultimately defeated by the angry maternal spirit of Laura Collins, who - summoned to defend the seemingly helpless boy David against Angelique - blasts the witch with supernatural energy and impales her upon the huge chandelier in the Collinwood foyer. During these final scenes, Angelique's face has begun to crack and collapse in a manner resembling that of a porcelain doll or eggshell, and as Barnabas speaks with her in her (apparent) dying moments, she is revealed to be virtually hollow inside. She reaches into her chest cavity and attempts to hand Barnabas her heart as proof against his assertion that she has no heart, but as she displays it the throbbing heart itself cracks and crumbles to pieces. Angelique relaxes, her eyes go vacant, and she appears dead.
However, the penultimate scene in the film reveals that Angelique has already set into motion her final act of vengeance upon Barnabas. His modern-era love, Victoria Winters, an apparent reincarnation of Josette who had been drawn to Collinwood in part by Josette's apparition, has been entranced by Angelique. Under the same sort of spell that doomed Josette, she has been sent to Widow's Hill and is forced to throw herself off the cliff there just as Barnabas arrives. Ironically, Barnabas is able to "save" Josette by using the very curse that Angelique imposed upon him: He plunges after Vicky and succeeds in transforming her into a vampire. Moreover, the vampirically revived Vicky utters the word "Josette," as she regains consciousness, suggesting that Barnabas has in fact been reunited - albeit in undead form - with Josette, thwarting Angelique's proclaimed intention that if she cannot have Barnabas, no one else will.