The Delivery Man (2015)

S37E07 What Are Dreams?

Every night, we slip into a world where logic bends and the impossible feels real—but why? Science is just starting to unlock the mysteries of the dreaming mind. NOVA follows pioneering researchers as they conduct remarkable experiments on the sleeping brain. From narcoleptics who collapse into sudden dreams to cats that act out their unconscious adventures, from haunting nightmares that repeat to people who never dream at all, each case offers a clue to one central, fascinating question: What purpose do our dreams serve?