Scooby-Doo! and Krypto, Too!

Plot

Months after the Justice League mysteriously disappeared, Lois Lane and Jimmy Olsen investigate the Hall of Justice but are chased out by a phantom, prompting them to call Mystery Inc. for help. En route to Metropolis, the gang find the city overrun by villains including Giganta, Solomon Grundy, Joker, Harley Quinn, General Zod, Non, Ursa, and Brainiac. Barely escaping to the Daily Planet, they meet Lois and Jimmy, who proclaims Daphne to be his girlfriend despite her protests, and they explain the situation.

Touring the Hall of Justice, they meet Lex Luthor, Mercy Graves, and Luthor's dog, Rex Ruthor. The phantom appears and menaces the gang, but a mysterious superpowered dog fends it off and initiates a lockdown. The dog is introduced as Krypto, Superman's pet, who befriends Scooby-Doo. Shaggy, Scooby, and Krypto raid the Kitchen but accidentally summon holograms of the Legion of Doom.

The gang finds holographic footage of the Justice League's disappearance, then Solomon Grundy infiltrates the building, instigating a chase. After Grundy vanishes in a flash of light, more phantoms appear. Velma deduces that Mercy Graves trapped the Justice League in the Phantom Zone using the Phantom Zone Projector to convert the Hall of Justice into her supervillain headquarters. Luthor hijacks the scheme, revealing he knew and used it to cover his plan to rule Metropolis with a robot army.

Rex, a robot, fights Krypto over the projector; Krypto wins despite Kryptonite in Rex's circuitry, uses the projector to trap the robot army, and frees the Justice League and Solomon Grundy.

Production

Development on the crossover began in 2021. James Gunn stated in February 2023 that all animated DC projects would be classified as DC Elseworlds. The following month, rumors claimed the film was canceled as a tax write-off for Warner Bros.

Discovery, and it leaked online. However, on July 26, 2023, it was confirmed the project was still active, with a trailer arriving the next day and a September 26 release date. This is the fourth time the late Joe Ruby and Ken Spears, who died in August and November 2020, receive special posthumous credit for a Scooby-Doo film.