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 United Artists Releasing.

Premise
Hans Truman retired in San Paradise from searching at mysteries, but Jason Truder and Stella Lee 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 retired detective.
 * Christian Slater as Jason Truder, Hans Truman's best friend.
 * Michelle Rodriguez as Stella Lee, a spy agent who is Hans Truman's love interest.
 * Kate McKinnon as TBD (confirmed to be voicing the main antagonist).
 * Bill Hader as TBD.
 * Jenna Ortega as TBD.
 * Olivia Newton-John as TBD. This will be Newton-John's final role as she completed recording her lines before her death in August 2022.
 * Nick Kroll as TBD.

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.

Music
In July 2022, composer Marco Beltrami was confirmed to be returning to score the fourth film, after withdrawing from scoring the third film.

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.

Video game
It was rumored on September 9, 2022, that Skydance New Media was teaming up with MGM to make a tie-in video game for summer 2023.