Dae-ho is in agony as his only son got kidnapped at a theme park. He gives up his career as a journalist in search of his son but to no avail. So-hyun, Dae-ho’s psychiatrist and a friend, suggests lucid dream, a new psychiatry healing method. The method is to have a patient fall asleep with awareness that he or she is dreaming, recalling lost memories to treat traumatic experiences. Instead of using this method as a treatment, Dae-ho decides to use lucid dream to search for his son. During this process, he faces various obstacles, side-effects, and unexpected acquaintances.