Some info and a short description of this South Park episode on South Park Zone:
South Park - Free Willzyx is episode 13 of season 9 of the Comedy Central series South Park. It originally aired November 30, 2005. The episode is based on the 1993 movie Free Willy, in which a trapped killer whale is freed.
Two aquarium workers trick the boys into thinking that a Killer Whale can talk, prompting the boys to liberate the animal and send him into space, which eventually lands on the moon.
South Park Spoiler Alert!
(The complete plot for this South Park Episode)
Our boys are at SeaWorld Park and find an orca there named Jambu (A reference to Shamu) performing in a whale show. Kyle stays to observe the whale in more detail while the others explore the rest of the park. To Kyle, the whale then seems to speak. However, the voice turns out to be coming through loudspeaker by Brian, one of the pair of hosts for the whale show. Mike, the other host, frequently play this practical joke for their own amusement. Brian, playing as the talking whale, tells Kyle about longing to go into outer space. Kyle rushes off to bring back the rest of the group. He manages to brings them back to the tank, but for a while Jambu remains silent, due to the announcers either reading or playing a video game. A few minutes later, when the announcers notice the boys' return, Jambu starts to speak again. The boys learn that Jambu, whose real name is "Willzyx", will die unless he returns to his family's home on the moon. The boys are in total shock at this and vow to do something.When the group return home they rally the rest of the 4th grade boys to help them liberate Jambu and send him "home". They break in to the Sea Park at night get Jambu into Clyde's pool from his backyard. When it is discovered that the orca is missing and an investigation is being carried out Brian and Mike realize what has happened and start to track down the group in pursuit.
The next morning at the Sea Park, Mike and Brian find that the boys whale-napped Jambu, and start panicking knowing that their prank has gotten out of hand. Rather than tell the police and park officials about their prank, let alone face the possibility of being fired, Mike and Brian decide that they must find the boys and retrieve Jambu before the police do.
In Russia, the government is looking for a way to raise money and they take a call from Kyle who wants to hire them to take Willzyx to the moon. When they give their price of $20 million, Kyle tries to explain what they are really trying to do, but the Russians believe that this is actually a prank call from George W. Bush. The boys decide to shop around for another Third World country with a cheaper space program, and they need to hide the whale.
Back at the Sea Park protesters from the Animal Liberation Front gather to show their support for the liberation of the whale. Meanwhile, Brian and Mike are searching South Park for the whale where they find the abandoned pool in the back of Clyde's house along with a broken fence. They observe that there are whale feces in the pool and that the boys have moved on. In fact, the whale has been moved to Kyle's bedroom where the boys are keeping him wet with garden hoses. Kyle is phoning the Japanese while Jimmy, Timmy and Tweek are at the Chinese Embassy, but everywhere they try the price is too high.
Stan and Craig are in Mexico, where they find that Mexicano Aeronáutica y Spacial Administración (MASA) will take their whale to the moon for $200. Brian and Mike find out that the boys are going to Tijuana.
Kyle, Kenny, Cartman, Butters and Clyde are on the road to meet Stan and Craig in Tijuana to get the whale home, when their truck is stopped by Brian and Mike. Just as the hosts are about to tell the boys the truth, the police arrive and demand that they give the whale back. However, the ALF comes to their rescue as the whale is saved in a hail of gunfire.
The ALF leader drives the van for the boys the rest of the way to the spaceport. In Tijuana, the rocket is being prepared. The ALF leader and the boys crash through the Mexican border, and the boys work on getting the whale into the water. Just before they do, Kyle says a tearful goodbye to him, which also brings tears to Clyde's and Butters's eyes. The whale finally gets into the water and the ALF is declaring victory when the manager of Sea Park arrives with the police.
The ALF celebrates victory and everyone else present watch the Mexican rocket get launched into space and they all realize what was being planned all along. The boys celebrate their victory back home. On the moon, the asphyxiated whale lies, as a reference to the ending of Space Cowboys. The end credits roll over this shot in silence.