An award-winning investigative Lee Strobal journalist -- and avowed atheist -- who applies his well-honed journalistic and legal skills to disprove the newfound Christian faith of his wife... with unexpected, life-altering results.
In 1980, Lee Strobel is an atheist journalist and investigative reporter for the Chicago Tribune. He and his wife Leslie have a daughter named Alison and are expecting their second child. After getting a very special recognition, Lee and his family go out to celebrate with dinner, where Alison chokes on a piece of candy. One of the patrons, a nurse named Alfie, intervenes and saves Alison. She credits the event to God's will, which Leslie takes to heart.
Leslie and Alfie become friends and start attending a Christian church together. Irritated, Lee unsuccessfully tries to dissuade Leslie. Due to advice from his mentor, Lee sets out to find evidence that proves that the resurrection of Jesus did not happen. Meanwhile, Leslie gives birth to a son, Kyle.
Lee starts gathering information and evidence. Next, he tries to prove that the witnesses were hypnotized, but a psychologist proves him wrong. Lee then tries to gather evidence that Jesus may have not actually died on the Cross, or was taken off, but again, a physician proves him wrong, saying Jesus had to have died on the Cross.
Meanwhile, Lee's estranged father tries to reconcile with him, but Lee brushes him off. His father dies soon after, and then Lee learns that his father truly loved him, which surprises Lee.
Simultaneously to Lee's pursuit to disprove the resurrection of Jesus, he is also investigating a case of a shooting of a police officer. At first, it looks like the convicted man is guilty and an informant for a gang, but Lee proves that the cop shot himself with a secret gun disguised as a pen, and the convict is freed.
Lee tries to get more evidence for his religious investigation, but his mentor explains that whether he chooses to believe or not believe, the last part of proving Jesus' real existence is faith. When a colleague gives him a speech, Lee decides to take the leap of faith and believe. When he tells Leslie about it, they have a happy reconciliation and pray together.