Ukradená vzducholoď (1967)

The film begins in Prague at the Jubilee Exhibition of 1891. Its main characters are five boys: Petr (Jan Malát), Pavel (Josef Stráník), Tomáš (Hanuš Bor), Martin (Jan Čížek), and Jakoubek (Míša Pospíšil), who happen to meet. The boys wander around the Exhibition Grounds and are chased away from everywhere. They then stumble upon a promotional event run by businessman Findeys (Čestmír Řanda), who is offering sightseeing flights over Prague in an airship. The airship is powered by a steam engine and is presented as steerable. A group of adult men are the first to pay for a sightseeing flight. But moments later they lose interest when they spot a balloon in flight that catches fire and has an accident. Findeys declares that his airship is filled with nonflammable gas, so nothing like that could happen to him, but this does not persuade the men to come back. Meanwhile, the main group of boys approaches Findeys’s airship and shows interest in a flight. Mr. Findeys promises to take them for free. The group of men who have paid for the flight then returns to the airship and says they want to fly. Findeys tries to throw the boys out, but they refuse to give up their promised free flight, untie the ropes securing the airship, and fly off. Findeys’s cashbox is also left in the airship’s gondola. All of this is watched and recorded by Marek (Stanislav Šimek), a photographer and reporter for the daily newspaper Světozor. The airship carrying the boys flies southwest from Prague. It then becomes clear that there is no coal aboard for the steam engine, and therefore the airship cannot be steered. During the flight, the crew of a military airship belonging to an unnamed country spots them. The military airship begins chasing the boys, but they manage to escape it. The country’s intelligence department, specifically Agent 13 (Karel Effa), is tasked with discovering the formula for the gas in Findeys’s airship. During the next leg of the journey, the boys’ airship encounters a storm and begins to descend. The boys try to make it as light as possible, throwing Findeys’s cashbox into the sea, among other things. Nevertheless, the airship keeps losing altitude and eventually crashes on an unknown island in the Atlantic Ocean. The boys escape from the airship unharmed, but it is then struck by lightning and catches fire—revealing that it was not filled with nonflammable gas after all. The boys set out to explore the island. They reach Captain Nemo’s fortress (Václav Švec, voiced by Zdeněk Štěpánek), where a feast has been prepared for them. Jakoubek also meets Captain Nemo in person aboard Nemo’s submarine. But Jakoubek runs away when Nemo asks him to play the violin. Meanwhile, other events unfold: the journalist Marek sets off in a balloon to rescue the boys. Findeys exploits the situation for publicity, claiming that it has been shown that even a child can control his airship. Sales of shares in Findeys’s company rise, and the military becomes interested in his airships. The military, however, has no idea that the claim about the nonflammable gas is a fraud. Millionaire Tenfield (Rudolf Deyl Jr.) and his daughter Kateřina (Jitka Zelenohorská) are returning to Bohemia aboard an ocean liner. The ship’s captain (Josef Větrovec) is engrossed in a card game with Tenfield and several sailors. He ignores the other sailors’ warnings that the ship is approaching land. The ship runs aground and is wrecked. Some of the crew take advantage of this to stage a mutiny. The captain, along with the loyal members of the crew, Tenfield, and Kateřina, is locked in the hold. Several mutineers go by boat to explore the island where the ship was wrecked, and it turns out to be the very island where the five boys are. Kateřina manages to escape captivity and also swims to the island, where she meets the boys. One of the boys has just been captured by the mutineers, but the others manage to free him with Kateřina’s help. Kateřina and the boys then succeed in freeing the captain and the captured members of the crew, and the mutiny is put down. The navy arrives at the island and rescues everyone. Findeys’s cashbox is recovered from the sea. Agent 13 also arrives on the island in a small airship, while journalist Marek arrives in his balloon. Using a listening device, Agent 13 overhears a conversation between soldiers in the hold of a warship. Findeys’s cashbox is opened in the hold, and among its contents they find an order for sulfuric acid intended for producing hydrogen, definitively proving that the supposedly nonflammable gas is a fraud. Agent 13 is distraught that he cannot complete his mission. The conversation in the hold is also relayed to journalist Marek. The news of the nonflammable-gas fraud is subsequently published in the daily newspaper Světozor. Findeys’s company shareholders revolt and rush into his house. Findeys escapes through a secret exit. However, the millionaire Tenfield pays for Findeys’s destroyed airship, thereby saving him from bankruptcy. In the final scene, the boys are going home by train and play at robbing it.