Josh Wheaton, a Christian college student portrayed by Shane Harper, embarks on a challenging journey when he enrolls in a philosophy class taught by the skeptical Professor Jeffrey Radisson, played by Kevin Sorbo. From the outset, Josh faces an ultimatum: sign a declaration declaring that "God is dead" to pass the course. Despite warnings from fellow students about the controversial professor, Josh is determined to stick with the class, knowing doing otherwise would disrupt his carefully planned schedule.
Radisson, an outspoken atheist, argues that the progress of science and reason has eclipsed ancient superstitions, positing that history’s greatest philosophers shared his beliefs. Unwilling to conform, Josh stands alone in refusing to sign, prompting Radisson to challenge him to a debate wherein his classmates will determine the victor. A single failure in this debate could jeopardize Josh's entire academic future, as it accounts for a significant portion of his grade.
In the midst of this intellectual battle, Josh forms a camaraderie with Martin, another student in the class. Meanwhile, his relationship with his girlfriend Kara, who has supported him since their high school days, becomes increasingly strained as she worries about the fallout from his stance against Radisson. They are at a crossroads—Kara, having attended her third-choice college to be with Josh, fears that his boldness could jeopardize their futures.
Guidance comes from Reverend Dave, played by David A.R. White, who emphasizes the inner doubts Josh faces as a sign of the Holy Spirit's influence, suggesting it is ultimately up to Josh to heed this calling. Over the course of the next few lectures, Radisson grants Josh the opportunity to defend the belief in God, leading to intense discussions. On multiple occasions, Radisson outmaneuvers Josh's arguments by citing esteemed scientists like Stephen Hawking, who suggest that the universe could arise spontaneously, devoid of divine intervention.
However, as the debates unfold, Josh counters with strong reasoning. He asserts that the universe’s existence requires a creator, pointing out anomalies in the theory of evolution and questioning the moral implications of a godless existence. Tensions escalate as Kara ultimately decides to break up with him, fearing the academic stakes are too high.
In a twist of fate, Reverend Jude, a visitor from Ghana supporting Dave, faces his own setbacks as the duo encounters vehicle troubles. As Josh and Radisson’s debates intensify, Radisson reveals his deep-seated pain stemming from the loss of his devout mother, planting seeds of doubt about his steadfast ideology.
The climax arrives during the third and final debate, where Josh boldly challenges Radisson: "Why do you hate God?" This poignant inquiry drives Radisson into a fit of rage as he divulges his resentment rooted in personal tragedy. In a startling moment of realization, Josh questions how one can harbor animosity toward someone they believe doesn't exist. Ultimately, Josh's courage inspires fellow student Martin to declare, "God's not dead," prompting a powerful wave of support from their classmates that leaves the professor in defeat.
Throughout this narrative, side stories intertwine, including Radisson’s relationship with Mina, a Christian he often belittles, whose self-acceptance journey leads her to stand up for herself. Additionally, the subplot of Mark, Mina's brother—an atheist shunning family ties due to his mother's illness—shows the struggles of faith and belief in the face of personal loss and societal pressures.
As the film builds to an emotional conclusion, themes of faith, resilience, and acceptance culminate in a Newsboys concert that celebrates the triumph of belief, showcasing a heartfelt tribute to the journeys of both Josh and the others affected by the overarching narrative of faith versus skepticism.
