The movie opens up during the Middle Ages, there were no doctors or hospitals, only medical experts known as Barbers traveled from city to city, with little knowledge of medicine. But in the Middle East, medical science was flourishing.
The scene changes to a small remote village, where several men work in a mine in England during 1021 A.D. A young boy named Rob who is also working at the mine, receives a loaf of bread as compensation for spending the whole day working at the mine.
On his way home, Rob notices a man surrounded by women, as he tells them jokes. He says that his name is Barber, and he boasts that he is a healer and has a cure for all diseases that befall them. While Rob is busy listening to the man, his loaf of bread gets stolen.
That night, Rob returns home empty-handed and sits with his mother, as she makes a prayer before they can eat dinner. In the middle of the prayer, his mother starts to feel sick, but brushes Rob’s concerns off when he asks her what is wrong. They go to bed that night, but Rob gets woken up in the middle of the night, as his mother starts screaming in pain.
When Rob touches her, he sees his mother’s impending death. Feeling helpless, Rob rushes to Barber, who had seen him in town earlier, and asks for his help. At first, Barber refuses to help but as the boy continues to insist, he gives in and follows him home.
When Rob reaches home, he finds his mother surrounded by the priest and the townsfolk. The priest spreads sacred oil on his mother’s body, and announces that his mother’s illness cannot be cured. When the priest notices Barber standing there, he claims that anyone who says they can cure the woman is going to get accused of practicing witchcraft.
Hearing this, Barber assures the priest that there is nothing he can do for the woman, and she dies. The following morning, Rob’s two siblings are taken away by the townsfolk while he is left behind. With no place left to go, Rob begs Barber to take him along with him, but Barber refuses and leaves the town.
In the middle of the night, Barber hears someone inside his carriage and prepares to attack, but he notices that it is Rob who has been hiding inside. Feeling sorry for the boy, he lets him spend the night with him. The next morning, he wakes up to find Rob curled up next to him and decides to keep the boy with him.
Years later, a grown-up Rob visits a new town with Barber, as he delivers the same speech that he had heard in his own town. The two of them put up an entertaining act everywhere, so that they could get more patients.
One day, the two of them visit a town where a farmer comes to them for a toothache.
Just before Barber yanks out the farmer’s tooth, he asks Rob to hold the man down as he struggles to see clearly. Just as Rob touches the farmer, he gets the same sensation he did during his mother’s death, and is able to foretell that the farmer is going to die.
Shaken up by his experience, Rob tries to tell Barber that the man is going to die, but he brushes off his concerns, and even jokes about it.
As the two of them leave a bar later that night, they are cornered by a bunch of men who blame them for killing their friend. They accuse Barber for practicing witchcraft, and lock him inside his carriage before lighting it up on fire.
Rob manages to save Barber, and treats his wounds far away from the town. One day, a curious Rob asks Barber if he has performed surgery on a dead body. This does not sit well with Barber, and he tells Rob not to bring it up again or the church will burn him at the stake for practicing witchcraft.
As days go by, Barber makes a full recovery, however, he feels like he will not be able to treat anyone, and his eyesight begins to fail. Rob begs him to let him help since he grew up watching Barber treat several people.
One day, the two of them head to another town to find people to treat. There, Rob performs his first amputation and continues to treat more people, as they begin to line up outside their tent. With days of practice, Barber finally seems Rob worthy of becoming a healer, and they celebrate his milestone together.
In the middle of the celebration, a woman tells Rob to take Barber to the town’s healer who will help take away Barber’s blindness. At first, he does not pay attention to what she is saying, and dismisses it by telling her that no one can treat blindness. However, as Barber’s vision begins to deteriorate, he changes his mind.
They arrive there, and meet the healer who agrees to perform surgery on Barber’s eyes. Days after the surgery, Rob takes off Barber’s bandage, and finds that his vision has fully recovered.
Impressed by his work, Rob asks the healer where he had learned to perform surgery. The healer tells him that he has learned everything from a place called Ispahan. When Rob asks him where the place is, the healer shows him a world map and points to its location in the Middle East.
He informs Rob that the world’s greatest healer known as Ibn Sina, a Muslim physician who teaches there and that no one can match his wisdom and knowledge.
Then, he informs Rob that Ibn Sina is in a place where Christians are not accepted, so he Sarcastically says that Rob has to pretend to be Muslim or Jewish.
Once Barber makes a full recovery, they leave the town and continue treating more patients. Rob expresses his desire to go to Ispahan and become a healer, also known as a Hakim by the Arabs, under Ibn Sina’s supervision.
To his dismay, Barber laughs it off and goes to sleep for the night.
The next morning, when Barber wakes up, he finds that Rob is not in his tent. He then takes his horse and follows after Rob. He manages to catch up to him and tells him that he will help him reach the docks. Once they reach the docks, Barber gives Rob extra money and bids him goodbye.
A year later, Rob finds himself in Egypt. There, he is given a haircut to blend in with the crowd.
He then meets up with a group of travelers, and accompanies them towards Ispahan. He even copies the way Jews pray, to make sure that he can convince everyone of his religion.
During his journey, he notices a beautiful girl traveling with them, but does not approach her, out of fear of being caught. One day, their leader points out that they have reached the Seljuks territory, a northern nomadic tribe that is well known for leaving a bloody trail behind them.
Their group heads towards a nearby town that they find filled with dead bodies. Rob is told that the Seljuks believe that they have been appointed by God to punish all the sinners. Just then, they hear the cries of a child, and find a young girl who is the only survivor among the townsfolk. On Rob’s insistence, they decide to take the girl along with them.
The woman he had seen earlier, is named Rebecca and she lets the young girl ride with her.
That night, Rebecca comes to get Rob and tells him that the young girl is sick. As Rob tries to bring her fever down, Rebecca reads the story of Aladdin to both of them. At this point, the young girl falls asleep, and Rob leaves the two of them to go back to his camp.
A few days later, the group gets stuck in a sandstorm. Rob leaves Rebecca behind to search for a few men who have gotten stuck in the sand. However, he ends up getting stuck as well and loses consciousness.
When he regains consciousness, he finds that Rebecca is gone, and he is left with one other man. The two of them begin moving forward but the exhaustion soon takes over, and the man ends up dying. With barely any energy left, Rob pushes himself forward and reaches Ispahan.
There, he excitedly tells them that he has come to study medicine under Ibn Sina. The men ask him for money or his recommendation letter, both of which he does not have. This is why they throw Rob out, and beat him until he loses consciousness.
When he regains consciousness, he finds himself in a bed. A man stands over him, who tells him that his wounds have been dealt with, and that he should feel better in a few days.
Rob curiously asks the man questions about what medications have been used on him. The man answers his questions patiently, and remarks that most of his patients don’t ask him this many questions. Rob replies that he wants to become a Hakim, and study under the great Ibn Sina.
A few days go by, and Rob makes a complete recovery. One day, he is woken up by a man who tells Rob that class is starting in a few minutes.
Although he is confused, Rob does not question it and follows the man to class. There, the man he had seen treating him is about to begin class. Rob joins the other students and thanks the man for talking to Ibn Sina on his behalf.
This causes everyone around to start laughing, and one of the students named Mirdin, tells him that he is in the physics class of Ibn Sina, and Rob realizes that the man who had treated him was Ibn Sina himself.
The next day, Rob and Mirdin head to class where Rob watched Ibn Sina with fascination despite not understanding much.
Over the next few weeks, he learns more about medicine and how Ibn Sina treats his patients. He even manages to impress Ibn Sina when he demonstrates how they fix dislocated shoulders.
The next morning, Rob walks with Mirdin where they meet Mirdin’s uncle, who is called Bar Kappara. He greets them and introduces them to the woman who is going to be his future wife. To his surprise, Rob finds that the woman is Rebecca, and the two of them pretend to not know each other,
Even though they are both heartbroken, they can’t do much and Rob is forced to attend Rebecca’s wedding celebrations. Before wishing her good luck, he hands Rebecca the storybook she had read for him during their journey.
The night of the wedding, still heartbroken, Rob ends up with another woman. As soon as he touches her, he senses her impending death. He rushes her to the institute and tries to find a cure for her.
Ibn Sina notices him and asks him why he has brought the girl with him when she looks in perfect health. Rob informs him that the girl won’t survive the night, and begins taking her shoes off. This is when the two of them notice a scorpion has bitten her, and the poison is already beginning to spread.
After successfully treating the woman, Rob confesses to Ibn Sina that he can tell when someone is about to die. Ibn Sina tells him to not look at his ability as a curse, rather he should see it as a gift.
Just then, they hear someone calling Ibn Sina and tell him that he is being summoned by the Shah, the ruler of the region.
He takes Rob along with him and as they enter the palace, they find that the Shah has mutilated a messenger sent by the Seljuks to negotiate a peace treaty. The Shah then sends the messenger back to the lord of Seljuks, who in retaliation kills the messenger as well, and sends a man plagued with the Black Death to Ispahan.
As the man arrives in Ispahan, he goes into the middle of the market and infects several people. This causes chaos to spread among the civilians.
They try to escape but the Shah orders the soldiers to close the gates, locking everyone inside. Rob overhears Mirdin’s mother telling him that Bar Kappara has left, leaving Rebecca behind alone.
He rushes to her house and finds her lying in the water to bring down her fever. He takes her back to the institute where she recovers. As the number of deaths per day goes up, Rob figures out that the disease has been spreading through fleas that are commonly found in rats.
As a result, they make a strong poison to kill the rats. Days go by and people begin to recover from the disease, and the city is once again opened for the people to come and go as they please.
Rob and Rebecca spend one last day together, as Bar Kappara comes back to Ispahan as well. One day, Ibn Sina gives Rob a patient who has been suffering from side sickness, the same sickness that took his mother away.
Although he is not able to help the man survive, Rob takes his body into a deep tunnel in the city and begins to dissect it. He begins to explore the man’s organs, and even finds that the side sickness was caused by the inflammation of an organ called the appendix.
Rob does not stop there, he goes deeper into the body and even illustrates pictures of the organs, and records everything he learns as he goes.
On the other hand, Rebecca falls sick and Mirdin goes over to her house to examine her. He finds that she is expecting, and that the child is Rob’s instead of his uncle, because his uncle can’t have kids. He warns her to try and deceive her husband, or she will die at the hands of the local priests also known as the Mullahs.
Instead of listening to him, Rebecca secretly makes her way into the city, so that she can meet Rob and tell him that they are having a child together.
Meanwhile, one of the Mullah’s followers discovers that not only is Rob a fraud, but that he has also been dissecting a body. Rob gets accused of Necromancy, a way of communicating with the dead to predict the future.
While he is being taken away, he notices Rebecca watching everything with tears in her eyes.
At the same time, Bar Kappara grabs Rebecca and discovers that she is expecting. A few days later, Rob is presented in front of the Mullahs who have accused him of Necromancy along with Ibn Sina, because they think he was helping Rob.
They claim that the two of them are to be blamed for their being punished by the Black Death. So, Rob is thrown into jail with Ibn Sina where he tells his master all about the workings of the human body.
During this, the Mullahs are summoned to the palace by the Shah, who has fallen sick with the side sickness. He orders them to free Ibn Sina and Rob, so that they can treat him. However, they threaten him by saying that the Seljuk leader would make a far better leader for their land.
Once they leave, the Shah sends his men after Ibn Sina and Rob and asks them to cut him open and cure his sickness. Rob agrees but in return asks the Shah to save Rebecca from getting killed.
Despite feeling nervous, Rob manages to cut the Shah open and remove his appendix. Meanwhile, the Seljuks, backed up by the Mullahs enter the city and begin wreaking havoc.
As the Shah recovers, he gets on his horse and prepares for a battle, knowing that he will die. He then directs Ibn Sina and Rob towards the city’s exit, and all of them leave along with their families.
However, Ibn Sina chooses to stay back in Ispahan because the patients need him, and to be close to his books.
Years later, Rob returns back to England with Rebecca, where he builds England’s first hospital. On the other hand, Barber uses the same slogans to try and attract patients, but a child tells him that all of them are at the hospital.
Shortly after, Barber finds out that Rob is still alive, and heads towards the hospital to meet up with him and his new family.