This is the story of Dominic Matei around World War II. He is a smart student who becomes a professor and then a 70 year old man. The movie opens with Dominic waking up and going to his favorite bar/restaurant (Café Select) in his pajamas in the middle of winter. He is intercepted on the way to the cafe and reminded of Christmas Eve and his under dressed condition. He returns grumbling about going to someplace where no one knows him. He has apparently lived a solitary existence because he has been preoccupied by his "work" (to find the origin of human language and how it evolved).

He goes to Bucharest to die carrying with him an envelope filled with poison. As he is walking down a street he is struck by a bolt of lightning which gives him third degree burns. He is taken to a hospital where he heals into a young man with supernatural powers (which he discovers as his life progresses).

He is helped out of the hospital by the doctor who nurses him. He publishes about his remarkable recovery and it arouses the interests of the Nazis. They send over a female spy who seduces him and talks with him in various languages. Dominic discovers he has an unnatural talent for learning languages in his sleep in addition to no longer seeming to age.

As his condition and abilities progress, Dominic becomes aware of an 'other' self who speaks to him in mirrors and his dreams. This other, who looks exactly like Dominic, serves as the voice of his condition and seemingly knows everything about his newly found power. His friend and caretaker discovers Dominic speaking to himself as he manifests two roses from thin air. This gives him great concern and understanding why the Nazis are so set on attaining Dominic for themselves, which leads to his helping Dominic escape. We learn later that this doctor died in a plane crash shortly after, whether this is connected to the Nazis remains ambiguous. Further isolating him, Dominic also finds that the Nazis confiscated all of the research conducted on his condition from his time in the hospital, effectively erasing his existence as anything other than an old professor who died in a storm.

He is pursued by the Nazis who attempt to duplicate the lightning strike. Upon failing they attempt to perform experiments upon him. He ends up running away with the assistance of the professor and many anti-Nazi sympathizers. Dominic is amazed to learn he has knowledge of how to forge passports and hide his identity while eluding his captors, living much like a spy throughout the war.

He escapes to Switzerland where he has an encounter with the Nazi doctor who was attempting to create a Nazi superman. Dominic flees from the doctor but is pursued to an alleyway where the two have a confrontation about the future of mankind. The doctor is forced to pull a gun on Dominic when he realizes Dominic will not willingly cooperate in the name of science, though the female Nazi spy who'd been tracking Dominic intervened when she realized while tracking him across Europe that she loved Dominic. The spy is shot defending Dominic, causing Dominic to panic and utilize another ability, mind control. The doctor struggles as his hand slowly places the pistol in his mouth and pulls the trigger, allowing Dominic to flee the country.

A series of newspaper headlines show the decline of the Third Reich, ending the war and allowing Dominic to resume a relative life of normalcy, which he uses to continue traveling. His fear of misuse of the information he's been gifted with, such as the fate and history of mankind, he develops a secret language for his diary only decipherable by a supercomputer in the year 2010.

While hiking he encounters a girl named Veronica and her friend driving up a mountain and tries to warn them about an approaching electrical storm but they continue up the mountain anyway. When the local authorities show disinterest in investigating the mountain to discover their fate, Dominic goes himself. Himself and a cab driver discover the car of the women had run off the road, with the driver dead several yards away. Dominic immediately runs to a nearby cave with a lightning-struck umbrella belonging to the other girl outside. He finds her huddled in the cave, chanting in Sanskrit, which he greets her in and takes her to a hospital.

Dominic finds Veronica now identifies herself as Rupini, the daughter of a wealthy family in India, among the first disciples of the Buddha. With this information, Dominic suggests to the hospital staff that they contact the College of Oriental Studies in Rome to verify this, which baffles the doctors who assume she is suffering from amnesia and delusion from the incident. Several scholars arrive and respectfully greet Veronica in Sanskrit as well. They verify that Rupini was a real person, who had gone to a cave many hundreds of years ago to meditate on Enlightenment at the Buddha's instruction. The scholars fund a research venture to find this cave in remote India and take Veronica to it to unravel the mystery. A holy man greets them outside the cave and directs Veronica (still believing she is Rupini) to the place of her meditation, which she immediately recognizes and runs to, but falls down a sharp slope and passes out.

The scholars investigate the cave with Dominic and find sparse furnishings covered in ages of dust, as well as the bones of Rupini. Upon discovering her bones, Dominic's 'other' explains he won't be needed for a time and fades away behind him. After her fall, Veronica becomes herself again and no longer speaks in Sankrit. Some time passes and she begins to fall for Dominic while in India on this expedition, after which they decide to 'get away' from all of the well-meaning media attention they had been receiving.

The two elope to a Malta where they are happy together until Dominic tells a sleeping Veronica that he loves her, and always has. Veronica begins to writhe around on the bed as if possessed and begins to speak in a language even he had no understanding of. The 'other' appears to him as well and explains that she is speaking in ancient Egyptian, but as Rupini. Dominic and the 'other' learn how to control this state in Veronica, which for the next two weeks continues to show Rupini regressing further and further back through time, speaking languages like Babylonian and older. Veronica's health begins to decline from the exhaustion of these sessions, and after being mistaken for a 40 year old woman (only actually 25), Dominic declares he cannot continue this for it would surely kill her at this rate. The 'other' disagrees and urges him in the name of science to use her to find the first language and complete his life's work. Dominic tearfully explains everything to Veronica, and leaves her weeping, begging him to stay.

Several years later, we see Veronica departing a train with her two children in France. Without being noticed, Dominic takes a snapshot of her and begins to cry when she passes without recognizing him. He returns to his college town where he taught as a professor and has an argument with his alter ego and shatters the mirror with his reflection. The 'other' is completely taken off guard, and yells "What have you done!?" over and over, slowly fading away. Before vanishing completely, the 'other' begins to gasp in an unknown language, then disappears.

Dominic returns to his favorite cafe that night to clear his thoughts, however while there he runs into all of his old colleagues, which is impossible as they were all very old when he first met them, which had been well over half a century ago. As more and more old friends from his past begin to join him and offering warm greetings, Dominic becomes more agitated and begins to age, complaining that this is a dream of a dream of a dream. Once reaching his actual age, he mutters to one friend that if he solves the problem he'll share it with them, which confuses everyone in the room. They ask "what problem Dominic?" to which he mumbles, "the one that we all have." Dominic stumbles out of the room and journeys out into the snowy winter night and dies at the bottom of a staircase. In the morning, a few townsfolk find his body greatly aged, and search his passport, belonging to a clearly younger man by a different name (depicting one of his aliases from the war.)