Chapter 4: Revolt of the Arithmetic Sequence

20/20 continues to combine hard-hitting investigative reports, newsmaker interviews and compelling human interest and feature stories.

Airport Chaplain Tobias Wallace has an unorthodox approach to solving the daily crises of an airport, constantly overstepping boundaries and putting him on a collision course with new boss Mira Ansari-Cole. Mira wants him fired but Tobias isn't giving up his beloved chaplaincy without a fight.

Criminal Minds revolves around an elite team of FBI profilers who analyze the country's most twisted criminal minds, anticipating their next moves before they strike again.

With the talent search open to acts of all ages, America's Got Talent has brought the variety format back to the forefront of American culture by showcasing performers from across the country. The series is a true celebration of the American spirit, featuring a colorful array of singers, dancers, comedians, contortionists, impressionists, jugglers, magicians, ventriloquists and hopeful stars, all vying for their chance to win America's hearts and the $1 million prize.

Set thousands of years before the events of The Lord of the Rings, this epic drama follows an ensemble cast of characters, both familiar and new, as they confront the long-feared re-emergence of evil to Middle-earth.