After installing a landline in their new home, Tyler and Chelsea begin to receive "unknown caller" phone calls from Ellen, an unstable woman who insists that Tyler is her ex-boyfriend, Eric. Mysteriously, the calls are coming from a ghostline, from which one can make phone calls without having a specific number. When neither the police nor the phone company can resolve this harassing headache, things become become hellish as they're now exposed to terrifying paranormal activity inside the house. Ignoring a warning to steer clear of the ever-dangerous Eric, the couple enacts a plan to prove to Ellen that Tyler is not the man she's after. Their final strategy backfires with deadly consequences in a shocking finale that will haunt you long after the film is over.