It’s a world where everyone tells the truth – and just about anything they’re thinking. Mark Bellison is a screenwriter, about to be fired. He’s short and chunky with a flat nose – a genetic setup that means he won’t get to first base with Anna, the woman he loves. At a bank, on the spur of the moment he blurts out a fib, with eye-popping results. Then, when his mother’s on her deathbed, frightened of the eternal void awaiting her, Mark invents fiction. The hospital staff overhear his description of Heaven, believe every word, and tell others. Soon Mark is a prophet, his first inventive screenplay makes him rich, and he’s basically a good guy. But will that be enough for Anna?
Mark Bellison (Ricky Gervais) is a loser about to lose his job as a screenwriter at a very successful production company, Lecture Films. He also has a lifelong crush over the perfect girl, beautiful Anna McDoogles (Jennifer Garner), but she doesn't want a fat, snub-nosed loser as her husband. That would ruin her chances to have perfect genetically beautiful, pretty babies. The setting for the story is somewhat odd. Nobody can actually lie about anything, they don't even know about the word as its not invented yet. Mark is about to get thrown out of his apartment for his inability to pay the rent. So, he goes to the bank to withdraw all his cash. But, there's a technical glitch in the computers and they ask the amount he has to withdraw from his account. He asks for $800 instead of $300 and the systems are back on. But, the lady says there must be a mistake as the system shows $300 and she gives him $800 thinking the system is corrupt! Here inadvertently, Mark invents the art of lying. He is the first person ever to lie and its as easy as drinking water to him and everybody believes whatever he says. His Mom gets sick, and he makes up a story about an afterlife to help comfort his Mom on her deathbed. Doctors and nurses overhear him, and soon Mark becomes an international authority on the afterlife. People camp on his lawn to learn more. Mark develops a story about the "Man in the Sky," who functions like God, and he pastes his theology on two pizza boxes like Moses and the Ten Commandments. Using his new-found power, he sways his old company and becomes rich and famous. He gets his girl, finally, and marries her.