Bill Maher travels the world questioning believers about faith, starting from a bar chart showing 16% of Americans identify as non-religious and building outward from there. He sits down with evangelical truckers at a Trucking for Jesus chapel, a Vatican priest who argues the Church itself doesn't take the virgin birth literally, Muslim clerics in Amsterdam, Scientologists, and a man in Jerusalem's Old City who claims to be the Messiah. Director Larry Charles shoots it like a rolling debate rather than a lecture, cutting between Maher's interviews and archival clips of televangelists, biblical epics, and news footage to needle the claims being made on camera. Maher pushes hard and talks over people, and the film doesn't pretend to be even-handed; it's an argument, not a survey. What holds it together is the specificity of who he finds and what they actually say when pressed, from a Puerto Rico satanist theme park owner to a genetics-minded priest, ending on Maher's own case that religious certainty is a global danger.