A guy is travelling through the mountains of Russia. It's part a long held ambition to travel the world that, at the age of 40, finally overcame him. He sold all his earthly belongings, bought Eurostar tickets to France, and has hiked his way to the Ural Mountains. He has thoroughly enjoyed his trip, and has no regrets.
However, he falls ill while walking through the mountains, and finds a monastery to take refuge in. The monks are part of a religious sect that has long since died out elsewhere in the world, but they're very friendly, and accommodating. They put the man up in a comfortable room, and make sure that he is well cared for. The man is content to spend his recuperation time here, in the monastery, as he becomes strong enough to continue on his journey.
One night, not long before he leaves the monastery, he hears a sound coming from deep inside the walls of the nearby temple. It's a soft, tapping noise. The man can't quite place the sound - it's familiar, but also mysterious. He hears it night after night, and it drives him to distraction. He visits the elder monk, and asks what the noise is. "I cannot tell you my son," says the elder, "for you are not a monk." The man accepts this, and goes back to his room.
But the sound continues, and he becomes more and more obsessed by it. He visits the elder once again, and asks to be inducted into the order so that he can be shown the source of the mysterious sound. "Alas my son," says the elder, "to become one of us, you must first pass three tests. These will test your endurance, your intelligence, and your very spirit. They may break you."
By this point, the man is willing to do anything to find the source of the sound, so he accepts the challenges put forward to him by the elder. His first test is to visit the ruins of an Incan temple in the Peruvian highlands, and recover an artefact long since lost to mankind. The temple is not on any maps, and will prove to be extremely difficult to find. The man spends many months travelling around Peru, looking for clues as to where this temple, and the artefact within, are located.
Eventually he happens upon a fellow explorer, Robert Mason, who claims to have been to the temple. Together, they set out using the hand drawn maps that Mason has created and the notes of his previous deadly excursion, in which the lives of four men were lost. They reach the temple after six arduous weeks of walking through the highlands of Peru, and endure the many traps that have been set to stop people from looting the temple.
They find the artefact, but Mason loses his footing on the way out of the cavern in which the temple is situated. As he dangles over the edge, the man is forced to choose between the artefact and his new found friend. He reaches for Mason's outstretched hand but fate takes the reigns, and Mason slips to his death. The man returns to the monks, sobered by his experiences but solemn in his desire to finally know what the mysterious sound is.
He hands the artefact to the elder. "You have done well my son. I am proud that you have finally recovered our lost artefact." The man asks to be shown the source of the sound, and relays his terrible tale of loss. But the elder monk gently refuses his request, for there are still two more challenges to be faced. The man is devastated, but accepts his fate and asks for details of the second task.
"Now, you must travel to Northern Europe, and recover for us an ancient sword used by the Scandinavian conquerors of legend. It was lost in the frozen tundra of the North."
The man travels first to Stockholm, where he asks for information in the local underworld. He is pointed to Tromso, in the far northern reaches of Norway. Travelling to this small town on the edge of the Arctic Circle, he is told that he must wait out the winter in order to pass through the treacherous terrain leading to the recently discovered Viking settlement that the sword is believed to reside in.
The man spends his time well. He trains heavily, wrestling polar bears and running through the snow covered hills. He recruits a team of hardened arctic explorers, including Roald Gustafsson, a famous geographer, and his family. The man is accepted into Roald's family over the course of the next few months as the two men become like brothers.
Finally, the weather clears and the two men leave with their team to visit the Viking settlement. The sword is located under a frozen lake, and as the man prepares himself to swim, the camp is attacked by a team of armed mercenaries who have been paid to recover the sword for a private collector in the United States. "Go, my friend," shouts Roald. "We will hold them off!"
The man breaks the ice and jumps into the lake, as he hears the screams from the battle behind him. It takes some time, but he locates the sword of legend, and cautiously swims back to the surface. He is not prepared for what he sees. Roald is dead, having been shot through the heart by a harpoon. The mercenaries are nowhere to be seen, save for their dead, having apparently been forced to retreat. They have killed the man’s crack squad of explorers alongside Roald.
The man returns to Roald’s family and together they give him a proper burial. His resolve is complete. The second task has been accomplished, and given the great personal tragedy he has endured, surely he will be allowed to finally know the source of the sound that has driven him insane for two years, and has now cost the lives of so many men.
The man is wrong. The elder thanks him for retrieving the sword, and sympathises with his plight. He mourns the dead and prays for their immortal souls. But there is one more task to be completed before the man can be fully inducted into the monastic order, and understand truly what the source of the maddening sound is.
The elder advises him to travel to Asia and return with knowledge of an ancient medicine, lost to humankind for hundreds of years. Only then will his training be complete.
He travels for years. He visits holy cities across the continent, from Hue to Lhasa, but has no success. He walks the length of the Great Wall of China, and travels the continent from top to bottom, left to right, in his fruitless search for answers.
As he is about to give up, the man finds strength and courage to continue, happening upon a small village in Eastern Cambodia. There, he finds the answers that he has sought for so long.
The knowledge of this medicine will help humankind, and most importantly he will finally know the source of the sound that has plagued him for ten years now. The deaths of Roald and Robert Mason will not be in vain.
He travels back to the monastery. He gives up the information. The elder, by now a very old man, is truly proud. He will induct the first new monk to the society in several decades.
There is a ceremony, and the man finally feels true enlightenment. He approaches the elder at the end of the day. “Master,” he begins, “Thank you. I feel truly blessed. But I must know the answer to the question I have asked you so many times. What is the source of the sound that has obsessed me and haunted my dreams for so long?”
“Ah yes my son. Truly you deserve the answers you seek,” says the elder. He finally leads the man to a secret room, deep within the monastery, and the man falls to his knees weeping uncontrollably as he finally sees the source of the sound. Ten years of his life are finally vindicated, and the deaths of all those men were truly not for nothing.