A MOTHER'S REVENGE, ON ABC NEWS' "20/20," FRIDAY, OCTOBER 5

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For Kim Cunningham, a mom from Knoxville, Tennessee, the world revolved around her children. So when she came to believe her son and daughter had both been sexually molested, how far would she go to protect her children, and what price would she pay for her actions? Cunningham shot dead one of the alleged molesters, who happened to be her older sister's live-in boyfriend, Coy. Deborah Roberts reports on a mother's revenge, on "20/20," FRIDAY, OCTOBER 5 (10:00-11:00 p.m., ET) on the ABC Television Network.

Plus: Twenty-five years after placing their baby, born out of wedlock, up for adoption, the unimaginable happens to a couple... they learn that the wife's employee is also their birth daughter. Bob Brown reports on an uncanny twist of fate.

And: Two middle-school boys were charged with five counts of felony sex abuse in the first degree because of what they did at an Oregon school to several 13-year-old girls. Was their spanking fellow female students in the butt really sexual harassment, as the prosecutor contended, and did it really warrant five days in jail? John Stossel reports.

Also: How far will people go to follow orders? A man posing as a police officer convinces fast food workers across the country to do unthinkable things to co-workers - all via telephone. How could a man be so convincing that strangers would act out his cruel requests? John Qui�ones updates his report from last year on this bizarre crime - including what happened to the Louisville, Kentucky McDonald's assistant manager and her fianc� who performed the caller's demands, as well as the man from Florida who was on trial for allegedly being behind the hoax.

"20/20" is anchored by Elizabeth Vargas and John Stossel. David Sloan is executive producer.