The film, directed by Ben Cotner and Ryan White, follows the legal battles of a gay and lesbian couple who fought to overturn the November 2008 ban in California on same-sex marriage, Proposition 8.
Since it's premiere,The Case Against 8 has received positive reviews. The Hollywood Reporter called the documentary a "stirring civil rights film that is both cogent and emotionally charged."
Hear more from the filmmakers in the Sundance video interview below. And look for the documentary to air on HBO in June.