The Plot Of James Gunn's Superman Sequel May Have Been Sneakily Revealed

We may receive a commission on purchases made from links.

James Gunn's "Superman" was the success that DC Studios needed. The film is now 2025's highest-grossing superhero movie, and audiences have largely fallen for David Corenswet's earnest and dorky take on the Man of Steel.

A sequel is certainly coming, but Warner Bros. Discovery has interestingly avoided the phrase "Superman 2." On WBD's Q2 2025 earnings call, CEO David Zaslav said that Gunn is writing the next "Superman family" movie. Gunn himself similarly told The Hollywood Reporter he's finished a treatment for the next "Superman saga" film. 

Keep in mind, the next DC Universe movie is going to be "Supergirl," carrying on from the surprise Kara Zor-El (Milly Alcock) cameo in "Superman." The running theory is that Gunn's next DC film is going to be a Superman & Supergirl team-up movie; that is, a sequel to two films in one. What threat could be so big that it needs two Kryptonians (and their dog) to face it? We may already know.

The behind-the-scenes feature "Adventures in the Making of Superman" (currently set to private on YouTube) features some custom made rough storyboards that Gunn uses to illustrate his childhood love of Superman comic books. One of the sketches (visible at the 2:18 time mark) shows Superman, Supergirl, and Krypto all flying together, hinting a sequel might indeed unite the trio. In the panel beneath them, there's also a bald head with several light bulb-like nodes on it. Superman fans will recognize who that is — Brainiac, one of Kal-El's deadliest enemies.

If nothing else, the idea of a Superman and Supergirl movie has clearly crossed Gunn's mind. (How could it not?) He has also said he considered using Brainiac as the villain of "Superman" before settling on Lex Luthor (Nicholas Hoult).

Created in 1958 by writer Otto Binder and artist Al Plastino, Brainiac has evolved a fair bit since his debut in "Action Comics" #242. Generally, he's depicted as a green-skinned alien. Sometimes, he's a cyborg, while at other times he's an artificial intelligence, but he's always as smart as his name suggests.

His goal is to collect knowledge, which he often does by visiting planets, shrinking down a city of his choice, and stuffing it into a bottle. One of his stolen cities is the Kryptonian city Kandor. He's sometimes called "The Collector of Worlds" for this reason.

Brainiac was originally depicted as coming from the planet Colu, but some later versions (particularly the cartoons "Superman: The Animated Series" and "My Adventures with Superman") have reimagined him as a Kryptonian AI. This gives him a much more personal connection to Superman. Based on what we learn about Krypton in "Superman," the Kryptonians creating an AI that turns into a planet raider sounds plausible.

But even without Brainiac showing up in these storyboards, he's the logical pick for the bad guy in a "Superman" follow-up. The first movie used Lex Luthor, so now use Superman's next biggest nemesis. Brainiac has somehow never been featured in a live-action film before (to compare: that would be like if the Riddler had never appeared in a live-action "Batman" movie), so his cinematic debut is long overdue.

But his arrival could portend something heartbreaking. The 2008 "Superman: Brainiac" comic by Geoff Johns and Gary Frank features Superman and Supergirl stopping Brainiac from destroying Earth. But Superman is so busy fighting, he  arrives too late to save his dad, who is suffering a heart attack. Clark and his dad's bond was a highlight of Gunn's "Superman," so watching Clark lose him could rival Peter Quill (Chris Pratt) losing his adoptive father Yondu (Michael Rooker) in Gunn's "Guardians of the Galaxy Vol. 2."

"Superman" is playing in theaters and has been released on home media. "Supergirl" is set to hit theaters on June 26, 2026.