After trying desperately to conceive a baby, Caitlin Bourke convinces her reluctant husband Paul to let her be artificially inseminated… with another man's sperm. At a prestigious fertility clinic, they choose a renowned music composer as their donor… or so they think. In another part of the same city lives taxi driver Billy Crapshoot. His handsome looks and slick personality mask a disturbing person… a ruthless carjacker and murderer who figures his only chance of becoming a father is to assume the identity of a donor.
In a bizarre twist of fate, Billy masquerades as the composer chosen by the Bourke's to father their child. When Caitlin joyfully discovers she is pregnant, Billy manages to discover her identity. Secretly stalking her, he becomes obsessed with the desire to destroy her husband and to posses both Caitlin and his unborn child. Caitlin finds herself on a terrifying journey into darkness where she has to fight the most important battle of her life!