In 1926, 13 years after his mother's death, illusionist Harry Houdini (Guy Pearce) has begun debunking mystics, psychics and others who claim to have paranormal powers. He offers US$10,000 to anyone who can quote his mother's dying words to him.Impoverished and uneducated Scottish con artist Mary McGarvie (Catherine Zeta-Jones) and her daughter Benji (Saoirse Ronan) set their sights on Houdini's reward when he visits Edinburgh on tour. Mary's psychic act pulls in the public: Benji surreptitiously gathers information on members of the audience, information Mary uses to con them into believing they can reach out to their deceased loved ones. Together, they are barely able to scrape up a living.Their only obstacle is Houdini's protective manager, Sugarman (Timothy Spall). Sugarman believes that Houdini is wasting his time with psychics and that he should abandon his quest altogether as this is showbiz and nothing is real. Mary starts by impersonating a maid at the hotel where Houdini is staying and gains access to his hotel room, but her search reveals nothing. Benji breaks into Houdini's ready room at the theatre and is caught by Sugarman. Benji tells Houdini that she is an assistant to a Psychic and says that Mary's (The Psychic) talents are real, and it is not an act. During one of his shows, Houdini has a vision of his mother, trying to tell him something. Somehow, this makes Houdini even more determined to see if she can be contacted from the physical world.Benji introduces Mary to Houdini. Mary says that process of connecting with the departed cannot be forced. It occurs naturally. Houdini decides to conduct a scientific experiment. He writes down his mother's last words in a letter, and locks it in a safe, to be kept in the Bank of Scotland. The letter will be opened only on the day of the Psychic experiment. The experiment will be conducted in front of the press, under scrupulous scientific conditions.Houdini is smitten with Mary and asks her out for lunch. Mary manages to charm the unsuspecting magician, but as they spend more and more time together, Sugarman intervenes, trying to prevent Houdini from becoming entangled with Mary, of whom he is suspicious.Sugarman's main desire is to see Mary and Benji gone; they claim they will be gone for good once they secure the reward for finding out what Houdini's mother said to him on her death bed. Sugarman realizes he can't get rid of them as easily as he had hoped. Mary is caught trying to open Houdini's chest and covers up by saying she was just searching for something to channel the psychic energy of the deceased. Sugarman tries to pay Mary to leave town, but she refuses. Benji falls into Houdini's water tank, which he uses on stage to demonstrate his escape routines. Inside the tank, Benji has visions of being visited by angels.Benji gets the key to the chest from Sugarman, who wants Mary and Benji out of Houdini's life forever. When Mary and Benji fail to turn up any useful information, they turn again to Sugarman. He tells them that Houdini was out doing a show and missed seeing his mother before she died. So, there are no words at all. Houdini was not there when his mother needed him the most.When the time comes, Mary is unable to perform the experiment and attempts to leave. At this point Benji starts having a fit on the ground and claims to be channeling Houdini's mother on her death bed, uttering the words of the Kaddish and addressing Houdini as "Ehrich", his real name, and speaking partly in German and partly in German-accented English asking where he is, and why he is not with her.This could be interpreted as either a genuine seance or a very skillful and convincing impersonation by the young artist. When the note he wrote to confirm the veracity of the experiment was removed from its safe and shown to be blank, Houdini reveals the "eternal shame" he feels because he wasn't able to reach his mother before she died, and thus was unable to comfort her in her moment of death, or to hear her final words. The McGarvies are awarded the $10,000.Mary is disgruntled because she believes Harry does not love her as she believed. When he says he does, they become romantically involved before Houdini leaves for his last performance, in Montreal. During his travels, he is climbing a set of stairs when a "Red-Haired Prankster" punches him in the stomach while he was not prepared, rupturing his appendix, eventually killing him.