The film follows a college freshman named Josh Wheaton (played by Shane Harper) who is enrolled in a philosophy course taught by Professor Radisson (played by Kevin Sorbo). On the first day of class, Radisson insists that all students sign a declaration stating "God is dead" in order to pass the course. Josh, a devout Christian, refuses to sign and Radisson challenges him to prove the existence of God in a series of debates.
As Josh prepares for the debates, he becomes increasingly isolated from his girlfriend, parents, and even his best friend who are all skeptical of his beliefs. Meanwhile, the film introduces several other subplots involving characters whose lives intersect with Josh's struggles, including a Chinese exchange student longing for religious freedom, a woman dealing with her boyfriend's cancer diagnosis, and a Muslim girl questioning her faith.
Through his debates with Radisson and interactions with these other characters, Josh argues that science and reason do not disprove the existence of God. He cites examples such as the complexity of DNA and the laws of physics as evidence of a higher power. Radisson, who is revealed to have a traumatic past that led to his atheism, becomes increasingly hostile toward Josh and ultimately suffers a fatal heart attack.
The film concludes with Josh successfully proving the existence of God to Radisson's former girlfriend (who is now a Christian), and the other characters resolving their own conflicts through prayer and faith. God's Not Dead was released in 2014 and was a commercial success despite receiving criticism for its one-dimensional portrayal of atheists and simplistic portrayal of theological debates.