The Sundance Channel is set to air the TV premiere of the documentary "Join Us" on the last day of August. The film, directed by two-time Sundance grand jury award winner Ondi Timoner, features gripping stories behind religion and cults.

"Join Us" will follow the stories of four families who flee their insular church and the pastor who controlled their lives. It will see the families through a two-week program at a cult treatment facility and back their homes in South Carolina, where they seek legal action against the pastor.

It will feature interviews with cultism experts, as well as the pastor himself, Raimond Melz, and his wife.

"Join Us" will air on August 31, Monday at 9 p.m. ET on Sundance Channel.