Operation Pluto was a plan during World War II to build a sort of underwater pipeline that would transport fuel from England to allied forces in France. It was like a really long hose that would go under the water and spit out fuel. The idea was that if the allies could get fuel to their troops quickly, they would be able to fight better and win the war.
The pipeline was made out of lots of segments of flexible tubing, which were all connected together. They were then wound up on big spools and shipped across the English Channel to France. From there, they were fed into the sea and laid along the bottom of the ocean.
The pipeline was really important in helping the allied forces. It meant that they could get fuel to their troops on a regular basis, without having to worry about transporting it by truck or plane. This was especially useful as the Germans had sabotaged a lot of the French oil refineries, which made it hard to get fuel in the traditional way.
Overall, Operation Pluto was a huge success, and helped the allies to win the war.