Tintin, Haddock, Snowy and Calculus are out on a vacation. Tintin and Snowy come down from a mountain. He urges Haddock to go trekking with him, but Haddock replies that he is better off resting in the hotel. He asks Tintin to be careful, reading out news from the newspaper. The news describes a plane crash, which happened to an aircraft journeying from Patna to Kathmandu.
Later that evening, Haddock and Tintin are playing chess at their dinner table. As Haddock plans out his moves, Tintin suddenly shouts out the sound “TCHANG”. The others scorn him, while Tintin tells Haddock that he was dreaming about his friend, Tchang Cho Chen, whom he saw fighting for life asmidst the wreckage of the crashed aircraft. Haddock asks him to get some sleep.
The next morning, Tintin comes out fresh and sound. A letter arrives and Tintin finds that Tchang has written to him, saying that he will be coming by air to Kathmandu. Something strikes Tintin and he sees the newspaper report. He is shocked to find that the plane that crashed was the same that Tchang described. More news unravels his name, saying that a change of flight might have been unlucky for him. Tintin breaks down. But suddenly, he gets up, determined to find Tchang. When Haddock is surprised, Tintin tells him that Tchang is alive because his guts tell him so. Reluctantly, Haddock agrees to accompany him.
Two days later, they arrive at New Delhi airport. Having a break of three hours, they decide to visit some spots in Delhi. While coming back, Haddock finds the road blocked by a squatting cow. As he gets onto the cow’s back to make it go away, the cow starts running, with Haddock riding it. It throws Haddock into a taxi, and the driver takes them back to the airport in the nick of time. A few hours later, they arrive at Kathmandu airport. Tintin talks to the manager about the crash, and the manager tells him that no one could possibly survive the crash and the cold of the Himalayas. But still, he arranges for a Sherpa to meet them. Later, Tintin and Haddock meet Sherpa Tharke. Tharke initially tries to coax Tintin into not venturing into the Himalayas, but when tintin decides to go alone, Haddock manages to have Tharke guide them.
Three days later, preparations are complete. Tharke arranges for some coolies(load-carriers) to accompany them with rations. The whole party sets off. Haddock has a lot of whiskey bottles with him, and makes good use of them from time to time. They spend the night in their tents and start off again the next morning. They encounter a river. Snowy licks some whiskey seeping out of Haddock’s bag, gets light-headed and falls into the river. Tintin saves him, though with a warning. Later, they come across some Tibetian tombs. The next day, the party crosses a big forest and reaches the foothills of the Himalayas. As they set down for dinner, Tharke warns Haddock that the mysterious Yeti is for real. As Haddock gets ready to open a bottle of whiskey, a Yeti screams nearby. Tharke warns him that the scent of whiskey will attract the Yeti. Haddock goes to sleep, grumbling.
The next day, they wake up to find the coolies disagreeing to go any further. Tharke manages to convince them and they come along. Haddock however finds his whiskey bottle missing. As the party journeys through the snow, they come across the Yeti’s footsteps. Haddock thinks that they belong to a bear. Following them, he finds his bottle lying in the snow, empty. He yells and challenges the Yeti to face him. His shouts cause a moderate amount of snow to fall upon him and bury him. Immediately, Tharke and Tintin rescue him. But when they return, they find the coolies gone, leaving behind the rations. Tharke discourages Tintin from going any further, but Tintin insists, saying that it will be pointless to return from here. They take the minimum essential with them and set off again.
Next morning, they reach the crash site. Tharke brings them to the debris of the aircraft. Tintin and Snowy decide to look around. Tharke and Haddock stay inside an intact part of the plane. Tintin goes further and finds a cave. He finds a stone, with Tchang’s name sculpted on it. As Tintin and Snowy come out, they face a blizzard. They go for a few steps, but with great difficulty. Tintin sees a shadow and thinking that it might be Haddock, follows it. His inattentiveness causes him to fall inside a hole. Snowy sensing trouble, stays there and howls.
After a few hours, the blizzard subsides. Haddock and Tharke hear Snowy’s howling and go to the place. They retrieve an almost frozen Snowy. Tharke goes inside the hole to find Tintin, while Haddock lets out rope. Haddock is suddenly distracted by Tintin’s arrival and lets go of the rope. But Tintin catches it and saves Tharke from falling. Later, Tintin recounts the incidents. He asks Haddock why he did not answer. But both Haddock and Tharke say that they stayed inside the aircraft during the blizzard. Tharke adds that Tintin might have seen the Yeti.
The next day, Tintin shows them the cave. They see Tchang’s name on the rock. But Tharke tells that the Yeti might have devoured him by now. Tharke tells him that it is pointless to search for Tchang, because they do not know which direction to take.
The next day, they prepare to return. Tintin suddenly spots a scarf, hanging from the mountain in front of them. Tharke sees it too. Haddock however sees not the scarf, but the Yeti through his field glasses. Tharke says that he must return, for it involves great risk to go near the Yeti’s dwelling. Tintin pays him in full. As Tharke walks away, Haddock joins him. Tintin manages to convince Haddock to join him. He attaches Snowy to his bag. The two of them start climbing the mountain. Haddock however makes a fatal mistake. He clutches a false rock and slips, hanging from Tintin’s rope in mid-air. Tintin fails to pull him up. But Tharke returns and saves Haddock. He says tht their indomitable courage to save Tchang has encouraged him to accompany them.
That night, another blizzard arises. Their big tent gets blown away in the wind. The small tent is too small for the four of them and snaps quickly. Tharke leads them on. However, Haddock drops tired soon. Tharke encourages them when he sees a monastery, but Haddock is simply too tired to get up. But a greater danger awaits them. The snow cracks above them, causing an avalanche and taking them with it. Later, Tintin however gets up. He finds his leg sprained and writes a letter of help, asking Snowy to deliver it to the monastery.
Back at the monastery, an old monk visualizes the party’s plight. Snowy arrives soon, and goes out with a group of monks to help Tintin and the others.
Two days later, Haddock finds himself in the monastery. He goes down to find Tintin and Tharke talking to the head monk of the monastery. The monk tells them that no one could possibly survive the crash. Tintin is disheartened, but still insists on going after Tchang. Haddock finally gets outraged and leaves him to go alone. The old monk comes and returns him Tchang’s scarf. But he visualizes again that Tchang is being held by the Yeti on a mountain near a certain village.
Tintin goes to the village. He is surprised to find that Haddock has come after him. They ask a little boy to show them the path to the described mountain, and leave the village. Two days later, they reach the higher altitudes. They spot the Yeti going out of a cave. Tintin goes into the cave, asking Haddock to warn him if the Yeti returns.
Tintin finds Tchang inside the cave, weak but alive. Haddock sees the Yeti returning and shouts out to Tintin to flee. But it is too late. The Yeti blocks Tintin’s path. Tintin tries to defend himself, but the Yeti almost has him cornered. However, its hand falls on the trigger of the camera slinging from Tintin’s neck. The flashbulb emits light and the Yeti gets frightened and runs out.
Later, Tintin and Haddock carry Tchang down from the mountain towards the village. Tchang describes how the Yeti found him and cared for him, feeding him and hiding him from the world. They are met by the monks from the monastery. The head monk gifts them a silk cloth of ritual value, praising all of them for their courage. A few days later, Tintin, Haddock, Tchang and Snowy return to Nepal along with a few other monks. Tchang feels sorry for the Yeti, saying that it is a gentle creature, despite its frightening appearance.