It is a cross-over between Alvin and the Chipmunks and the High School Musical franchise taking place six months after the 2008 film High School Musical 3: Senior Year. Because of this, Wildcat Spirits Forever! is the only C.T.S. story to be a song-fic (due to FanFiction.net's "No song-fics" rule, the song-fic elements are not present in that version).
However, due to its having been written prior to the October 24, 2008 theatrical release of HSM3, certain aspects of Wildcat Spirits Forever! were contradicted by events in the finished HSM3 motion picture, such as the surname of the Donny Fox character (named Donny Dion in the finished film), post-East High fates of certain HSM characters, and so on.
The story begins with a Prologue recapping the cliffhanger ending of Ohana, Interrupted with Troy Bolton's marriage proposal to Gabriella Montez in front of the entire United Galactic Federation Grand Council.
The story picks up with Gabriella's acceptance of said proposal, leading into an impromptu singing contest between “Team Chipmunk” (Alvin, Brittany, etc. except Troy and Gabriella) and “Team Montez-Bolton” (Troy and Gabriella) (“Start of Something New”).
The contest is deemed a draw. With that, the “Chipmunk Adventure 20th Anniversary World Tour” staff returns to Earth to tie up a couple of loose ends-most notably executing Kelsi Nielsen's plan to bring Lilo Pelekai and Keoni Jameson together. With the plan's success, the Tour-now counting Lilo, Keoni, Stitch, Angel and Zeo amongst its staff-travels on to Albuquerque, New Mexico.
Troy sees an opportunity to inform his fellow “Honorary Wildcats” of his pending nuptials and asks Alvin to send a message.
Upon their arrival in Albuquerque, Alvin receives a call from friend and Italian pop star Isabella Parigi, informing them of her own upcoming wedding.
Isabella asks to personally tell her “doppelganger,” Lizzie McGuire. However, Lizzie herself is in the midst of receiving her own marriage proposal, from long-time friend-turned-boyfriend David “Gordo” Gordon, on a holographic reproduction of the Rome, Italy rooftop where their relationship began. She accepts. (“What Dreams Are Made Of [Ballad Version]”)
Finally, the Honorary Wildcats arrive at the Astro Megaship's landing site. It is then that they are made aware of Troy and Gabriella's engagement.
Later, the Tour staff perform a concert at East High School to kick off the new school year. During this concert, we meet Kylie Styles (Joanna Pacitti in the Seville Library version)--the singer whose song "Watch Me Shine" was the cut-off in the Leroy clone during Ohana, Interrupted--in the flesh for the first time.
Lilo informs U.G.F. Grand Councilwoman Khandravex about Kylie/Joanna. With Khandravex en route to Earth, Alvin orders all Tour personnel to be on board when she arrives.
Meanwhile, Troy is at the ski resort where his relationship with Gabriella began, while Ryan Evans and Kelsi are on one of the MegaShip's simudecks watching a movie, then experience their first "romantic encounter" (although it is only implied in the FanFiction.net version that this takes place).
Finally, Khandravex arrives on Earth and gives Kylie/Joanna the Hero's Cross. Shortly thereafter, Ryan and Kelsi teleport to the East High auditorium where Ryan proposes to Kelsi. She accepts.
We fast-forward to Troy and Gabriella's wedding day, where Jason Archer acts as Gabriella's father of the bride. Team Chipmunk serenades Troy and Gabriella before they officially become husband and wife ("You Are the Music in Me").
Alvin, Simon, Theodore, Brittany, Jeanette, Eleanor-Owned by Bagdasarian Productions, Inc.
Max Goof, Roxanne Martin-Goof, Lizzie McGuire, David "Gordo" Gordon, Isabella Parigi, Paolo Valisari, Ren and Louis Stevens, Kim Possible, Ron Stoppable, Rufus, Launch (Experiment 607), Dr. Mr. Possible, Dr. Mrs. Possible, Dr. Drakken, Shego, Bonnie Rockwaller, Señor Senior Junior, Lilo Pelekai, Nani Pelekai, David Kawena, Stitch (Experiment 626), Angel (Experiment 624), Gantu, Reuben (Experiment 625), Keoni Jameson, Kelsi Nielsen, Troy Bolton, Gabriella Montez, Chad Danforth, Taylor McKessie, Sharpay Evans, Ryan Evans, Principal Matsui, Jimmie Zara, Donny Fox/Dion, Tiara Gold-Owned by Disney Enterprises, Inc.
Jett Jackson-Owned by Echo Bridge Entertainment (as successor-in-interest to Alliance Atlantis Communications, Inc.) and Disney Enterprises, Inc.
Jason Archer, Melinda Crosby, Zeo (Jookiba Experiment Offspring Alpha), Melissa Anne Benson-Owned by the Author.
Johnny 5-Owned by TriStar Pictures.
All The Price is Right references-Owned by Fremantle Media North America, Inc.
Rebecca Hawkins-Owned by Studio Gallop and Kazuki Takahashi (U.S. character name owned by 4Kids Entertainment, Inc.).
All Power Rangers references-Owned by SCG Power Rangers, LLC./Toei Company, Ltd.
Chipmunk Tour Trivia
For reasons similar to chapters 5 and 6 of Ohana, Interrupted, the majority of Wildcat Spirits Forever! was edited in 2009. This was because William Raymer had severed all ties to actress-singer-songwriter Joanna Pacitti following Pacitti's disqualification from the reality television series American Idol.
Pacitti was replaced by Kylie Styles, a character from the television series Power Rangers: DinoThunder.
Pacitti is in the process of reinstatement to the Chipmunk Tour Saga-William Raymer is re-editing the C.T.S. stories for The Seville Library, a repository for Alvin and the Chipmunks fan fiction.