In Bloody Birthday, the three children born during the eclipse are Debbie, Curtis, and Steven. They live in a suburban neighborhood and attend the same school as the main characters of the movie, Joyce (the teenage sister) and her younger brother Timmy.
Despite their seemingly normal appearances, Debbie, Curtis, and Steven are sociopathic killers. They have no empathy or remorse for their violent actions, which range from shooting arrows into a woman's back to suffocating a child with a plastic bag. They also have a twisted sense of humor, often taunting their victims before killing them.
Joyce and Timmy unwittingly become involved in the murders when their friend is killed by the trio. Suspecting foul play, they begin to investigate and eventually discover the truth about Debbie, Curtis, and Steven. However, the children are able to manipulate their way out of suspicion by appearing innocent and charming.
As more people in the neighborhood turn up dead, Joyce and Timmy become increasingly desperate to stop the killers. They eventually enlist the help of a police officer and set a trap for the children. In a brutal showdown, the trio is finally brought to justice.
Bloody Birthday is a disturbing and bloody thriller that explores the dark side of childhood innocence.