Upside Mystery Legacy

Upside Mystery Legacy is an upcoming American fantasy mystery film produced by MGM Animation Studios and Spyglass Media Group, with animation set to be provided by Cinesite and MGM Animation Canada. The film is directed by Simon J. Smith from a screenplay by Jeff Gunn, William Schifrin and Ray DeLaurentis, and will feature the reprised voices of John Travolta, Christian Slater, and Michelle Rodriguez, with Kate McKinnon, Bill Hader, Jenna Ortega, Olivia Newton-John, and Nick Kroll joining the cast. It will be the fourth and final installment in the Upside Mystery franchise. This film will be dedicated to Olivia Newton-John, who died on August 8, 2022, from breast cancer.

The film is set to be released in the United States on July 7, 2023, by MGM Studios.

Premise
Hans Truman retired in San Paradise from searching at mysteries, but Jason Truder (Hans' best friend) and Stella Lee (now Hans' wife) received the last mystery from the Upside Mystery headquarters, convincing Truman to come out from his retirement on a terrifying last mystery.

Cast

 * John Travolta as Hans Truman, a legendary detective and later Stella Lee's husband, who comes out of his retirement for his last mystery.
 * Christian Slater as Jason Truder, Truman's best friend who was also good in solving mysteries.
 * Michelle Rodriguez as Stella Lee-Truman, a spy agent who is now Hans Truman's wife.
 * Kate McKinnon as Meryl Farr.
 * Bill Hader as William Wilson.
 * Jenna Ortega as:
 * Gena Truman, daughter of Hans Truman and Stella Lee.
 * Samantha "Sammy" Mintz.
 * Olivia Newton-John as Bianca Tuffin. This will be Olivia Newton-John's final role, following her death in August 2022, and this film will be dedicated to her memory.
 * Nick Kroll as Andrew Slatter.
 * Christina Ricci as Kelly France, a former physicist who became the new boss of the Upside Mystery headquarters, replacing Rose Elizabeth.

Development
When asked about MGM making the fourth film, John Travolta stated "We're not entirely sure. We are already open to ideas. We'll see when that happens." On April 16, 2019, it was announced that the fourth Upside Mystery was in development, with Travolta, Christian Slater, and Michelle Rodriguez reprising their roles, Simon J. Smith directing, and will be written by Jeff Gunn, William Schifrin, and Ray DeLaurentis. In the event of 15th anniversary of the first film, Travolta confirmed that the fourth installment will be the "last" while describing the film to have a more "serious and mature" tone than the previous installments. He also revealed that Kate McKinnon and Olivia Newton-John have joined the cast in the final installment. Spyglass Media Group was also revealed to be returning to co-produce the movie, with Gary Barber and Peter Oillataguerre executive-producing. On March 21, 2022, it was announced that the title will Upside Mystery Legacy and was set to be released on July 7, 2023. In addition, Bill Hader, Nick Kroll, and Jenna Ortega also joined the cast. Unlike the first three Upside Mystery installments, which were provided by Arc Productions in Toronto, the animation services will be provided by Cinesite in Montreal and Vancouver, and MGM Animation Canada in Montreal. In September 2022, Christina Ricci confirmed that she will reprise her role as Kelly France from Upside Mystery 3.

Music
In July 2022, composer Marco Beltrami was confirmed to be returning to score the fourth film, after initially departing from scoring the third film. Buck Sanders later joined to co-compose the score with Beltrami on December 16, 2022.

Release
Upside Mystery Legacy will be released on July 7, 2023, taking over the release date of Madame Web. It'll be shown in RealD 3D, Dolby Cinema, IMAX, 4DX, and ScreenX formats. Warner Bros. Pictures is set to distribute this film internationally as part of their new multi-year pact deal with MGM.

Marketing
MGM's official YT channel released a teaser trailer on August 3, 2022, and was released in front of Hailey in theaters. On December 1, 2022, a new trailer was released by MGM YT channel and Warner Bros.' international YT channels.

Video game
In October 2022, it was announced that MGM would collaborate with Skydance New Media for a tie-in game.