In 1967, experimental filmmaker Jorgen Leth created a striking short film, The Perfect Human, starring a man and women sitting in a box while a narrator poses questions about their relationship and humanity. Years later, Danish director Lars von Trier made a deal with Leth to remake his film five times, each under a different set of circumstances and with von Trier's strictly prescribed rules. As Leth completes each challenge, von Trier creates increasingly further elaborate stipulations.

Waking Life is about a young man in a persistent lucid dream-like state. The film follows its protagonist as he initially observes and later participates in philosophical discussions that weave together issues like reality, free will, our relationships with others, and the meaning of life.