Unlike most TV dramas based on real-life events, there are no villains in "Switched At Birth." Just two families whose lives are tormented by a tragic mistake.

The two-part movie airs Sunday and Monday at 8 p.m. on Ch. 2.In 1978, Bob and Barbara Mays (Brian Kerwin and Judith Hoag) become parents of a daughter in a small Florida Hospital. A couple of days later, Ernest and Regina Twigg (John M. Jackson and Bonnie Bedelia) have a daughter at the same facility.

What no one is aware of is that the babies go home to the wrong families.

Young Kimberly Mays is healthy and happy - but her mother dies of cancer when the child is only 2.

Arlena Twigg, on the other hand, suffers from heart disease and dies after surgery at the age of 9. Subsequent genetic tests show Arlena could not possibly be the Twiggs' child.

It's a nightmare made all the more horrifying because these events actually happened. And, fortunately, this is a very good production. It's evenhanded and lets the tale tell itself without much embellishment.

Of course, it doesn't need much embellishment

Bedelia is excellent as the mother anguished by her daughter's death, then the knowledge that she has a child out there somewhere. And Kerwin is equally good as the conscientious father who fears losing his only child.

That's what makes this drama different. These are all good people caught up in a horrible situation.

They are not perfect people. The Twiggs are, at times, almost fanatical in their search for their missing daughter. And Bob Mays' refusal to see their point of view can be difficult to watch.

If this were fiction, these people would be able to come up with a good solution to an impossible problem. But this is real life, so we learn at the end that the two sides are still battling it out in court.

That doesn't lessen the impact of "Switched At Birth" - it makes it all the more poignant.