INSIDE FAMILY MINEFIELDS: IN A SPECIAL EXTENDED �PRIMETIME,� DIANE SAWYER EXPLORES THE COMPLEX ISSUES OF BLENDED FAMILIES, FOLLOWING TWO FAMILIES AS THEY STRUGGLE TO FIX RELATIONSHIPS SPIRALING OUT OF CONTROL, FRIDAY, APRIL 21 ON ABC

When parents re-marry, the newly formed family can be laced with minefields ready to explode. In a special �Primetime� report, Diane Sawyer explores the complexities of the stepparent-stepchild relationship and how to cope with the unique issues brought by today�s merged families. In a rare shoot schedule, �Primetime� captures 1500 hours of video shot over three years of two families on the brink. The remarkable footage exposes just how bad things can get within so-called blended families. And like many families � blended and not blended � their stories reveal shifting alliances, daily subversions and tensions that can escalate to marital crisis and hostility. Sawyer interviews experts who analyze the videos and provide insight into handling some of the serious problems the families face. �Primetime� airs FRIDAY, APRIL 21 (9:00-10:45 p.m., ET) on the ABC Television Network.

Today, being part of a stepfamily is common, but there is little information available to help families navigate the complexities they�ll face. Two families agreed to place cameras in their homes to show �Primetime� first-hand how these dynamics play out. There are lessons here for all families, not just stepfamilies.

First, there is the modern day �Brady Bunch,� the Alsteads of Snohomish, WA. Laurie, a marketing executive, has four kids of her own, while Tony, a corporate project specialist, has two. When they marry, it adds up to eight under one roof. But that�s where the similarity between the Alsteads and the Bradys ends. It�s quickly apparent there�s a tug of war in parenting styles. Laurie�s sergeant-like parenting approach conflicts with Tony�s freestyle ways, and their hopes of getting the family to engage in teamwork instead turns out to be fantasy. As tension escalates between each step parent and their stepchildren, the friction takes its biggest toll on the marriage. The reality is a day-to-day struggle of anger and frustration for everyone � and a family in crisis.

Three thousand miles away in Lake Placid, NY, the Nelson family is encountering a different set of problems which will eventually put the father between his new wife and his daughter. Their problems escalate to an even more brutal level.

After having his daughter, Kyle, from his first marriage, Joe Nelson enters a second marriage to his wife, Lynn, with whom he has three children. Initially Lynn tries to be a second mother to Kyle, who pulls away, resulting in hurt and anger from Lynn. Years later, when Kyle comes to live with Lynn and Joe, Lynn�s often reacts with bitterness toward Kyle. She becomes threatened by Kyle's strong relationship with her younger stepsiblings. According to Dr. Scott Browning of Chestnut Hill College, �I think Lynn is frightened that Kyle is too popular with her children.�

For the Nelsons, tensions mount, arguments turn volatile and Lynn�s behavior is explosive � especially towards Kyle. Kyle says she is afraid of her stepmother because she fears Lynn will abuse her. While Joe and his wife dismiss Kyle�s fears as an exaggeration, the tapes allow viewers to judge for themselves. And although Kyle adores her father, she cannot compete with her stepmother for his attention. Lynn's vitriolic outbursts place Joe in the middle.

�Primetime� then sits the families down with experts, who guide them through revelations and understanding. But can these households � and the millions in similar situations -- be saved?

DIANE SAWYER, CHRIS CUOMO, CYNTHIA McFADDEN and JOHN QUI�ONES are the anchors of �Primetime.� DAVID SLOAN is the executive producer.