'20/20' FEATURES FIRST ON-CAMERA INTERVIEW WITH ELIZABETH THOMAS, STUDENT TAKEN BY TENNESSEE TEACHER RESULTING IN 38-DAY NATIONWIDE MANHUNT

'20/20' Airs Friday, Sept. 21 (10:01 - 11:00 p.m. EDT), on ABC

"20/20" features first on-camera interview with Elizabeth Thomas.

"20/20" features the first on-camera interview with Elizabeth Thomas, who was taken at age 15 by her Tennessee high school teacher Tad Cummins, resulting in panicked friends and family and a 38-day nationwide manhunt. In the interview, Elizabeth opens up to ABC News correspondent Eva Pilgrim, saying Tad had a gun in his car and threatened to harm her and her family unless she left town with him to start a new life. The full interview airs on "20/20," Friday, Sept. 21 (10:01-11:00 p.m. EDT), on ABC.

"20/20" features interviews with those closest to Tad and Elizabeth who describe the relationship between the two and what they think led him to take her in March 2017. Pilgrim retraces their journey from Tennessee to a remote area in northern California, investigating how these two were able to remain hidden when authorities across the country were searching for them. This hour includes interviews with Jill Cummins, Tad's wife, who has filed for divorce; Ashlee Conner and Erica Osborne, Tad's daughters; Anthony Thomas, Elizabeth's father; Josh and Sarah Thomas, Elizabeth's siblings; Jason Whatley, Thomas family attorney; District Attorney Brent Cooper; and Griffin Barry, the man whose tip led to Tad's arrest.

After Elizabeth's mother was removed from their home for alleged child abuse while homeschooling her children, Elizabeth and her siblings began attending public school. Elizabeth's mother denies these allegations. Tad's wife, Jill, believed that she and Tad were helping Elizabeth deal with the alleged abuse she faced at home and saw Tad and Elizabeth's connection as a father-daughter relationship. In late January 2017, a middle school student claimed to have seen Tad and Elizabeth kissing in his classroom. After Tad was ordered by the school to stay away from Elizabeth, he was suspended when he violated the order. After being on the run for more than a month, Tad sought refuge with Griffin - a stranger who provided shelter in exchange for manual labor - in northern California. Soon after, Griffin realized who they were and alerted authorities. In April, Tad pleaded guilty to taking a minor across state lines for sex and to obstructing justice. He will be sentenced later this year, facing a minimum of 10 years.