Tintin wonders why it is so hot, and opens the window. He sees that the star is getting bigger every minute. He walks to the Observatory, and, after some trouble, gets inside.
Inside, he meets a man called Philippulus who proclaims himself to be a prophet and tells him that "It is a Judgement! Woe!" Puzzled, Tintin proceeds to the main room with the giant telescope. There he meets the director of the observatory, Professor Decimus Phostle, who explains that the extra star is a vast ball of fire making it way towards Earth, which will cause the end of the world.
Tintin comes back home and struggles to sleep. Next day, in the morning, the meteorite crashes on Earth, cusing a violent earthquake in the process.
Tintin makes his way to the observatory, and is surprised to find the Professor elated, having hypothesized the occurance of an unknown mineral on the meteorite. But suddenly, a radio broadcast says that the meteorite has landed in an ocean. The Professor breaks down, but Tintin shows him that the meteorite might still be floating due to its large size. The Professor congratulates him and Tintin goes to search for his friend, Haddock to charter a ship.
In a few days' time, a group of scientists including Phostle, Tintin and haddock embark on the journey. They hire a ship named "Aurora", with a sea-plane on board. Snowy's annoying pranks begin the moment he smells food.
But elsewhere, conspirators try to foil the Aurora's journey. They launch a ship of their own, the "Peary" and give it specific instructions to block the Aurora's passage.
The first night, a huge storm rises over the sea. Haddock struggles to maintain control. Suddenly they notice aa ship moving without lights and almost upon them. They steer away in the nick of time.
The next day, the Aurora reaches the Arctic Circle and the temperature falls to near zero. The Aurora stops for re-fuelling at a gas station. But conspiracy does not leave them. The manager refuses to give them oil. The Captain meets an old friend, Chester and talks about his expedition. They hatch a plan to fuel the Aurora. They succeed and the aurora sets sail the next day.
They launch the sea-plane with Tintin and the pilot as passengers. The plane flies towards the meteorite and has a visual. while returning, Tintin spots the Peary closing on the meteorite. He messages Haddock to increase speed. The plane returns and Haddock increases speed.
The next day, the Aurora recieves an S.O.S. Haddock orders the ship to turn away. But Tintin feels that something might be fishy. He browses through a catalogue and fails to find the distressed ship's name. Captain realizes that they have been tricked and orders full speed drive toward the meteorite.
Suddenly, the aurora intercepts a signal from the Peary. It says that the Peary has a visual on the meteorite. Tintin orders the sea-plane to be prepared. But Snowy does not want to be left behind. He jumps onto the port-wing of the aircraft.
Haddock messages Tintin of Snowy's act and Tintin comes out of the cabin and plucks him up from the wing. Before long they reach the meteorite and see the Peary launching a dinghy. Tintin jumps with the flag and parachutes down upon the meteorite. He plants the flag in the nick of time and claims the meteorite for his team. The Aurora finally beats the Peary.
Snowy jumps onto the island. Tintin says that he will stay on the meteorite. The pilot gives him a ration of food and flies back to the Aurora.
Next morning, Tintin is suddenly woken up by an explosion. He sees mushrooms growing rapidly and exploding. An apple sprout pops up and becomes a tree within minutes. A giant apple falls on Snowy and hurts him. Suddenly a giant spider comes out and chases Tintin. But suddenly an earthquake occurs and two apples fall, the first killing the spider and the second, landing upon Tintin. He faints and Snowy bites his butt to wake him up.
Earthquakes shake the whole meteorite. Tintin realizes that it is sinking. But thankfully, the sea-plane returns and lands in the water successfully. The pilot launches a dinghy and Tintin gives Snowy to him. He returns to the meteorite and manages to pluck out a chunk of rock, just before the meteorite sinks completely.
Within a few hours, the sea-plane returns to the Aurora. Tintin tosses over the rock to the group of scientists and a mushroom pops up and explodes in their faces.
The next day, radio broadcasts over the country spead the news of the Aurora's success. Also the name of the conspirator is spelled out, threatening to bring him to justice.
The Aurora finds land. Both the ship and Haddock need a refuel, the former, in kind of oil and the latter, in kind of whiskey.