A babysitter (Rebekah Kochan) begins a job with a new family in Southern California, but soon experiences unsettling phone calls from an unknown man she initially believes is her boyfriend (Robert Buckley). When his friends show up (Sarah Hall), she realizes the caller isn’t who she thought. Chaos follows. "When a Killer Calls" (2006) fits squarely within the slasher tradition of 1970s films like “Home for the Hol…