Captain America: Brave New World Is Weirdly a Sequel to The Incredible Hulk

Credit - Disney+

Warning: This post contains spoilers for Captain America: Brave New World.

The Incredible Hulk has been buried in the annals of MCU history. Released on the heels of the wildly successful Iron Man, the 2008 Hulk solo film was supposed to help build out the new Marvel Cinematic Universe and seed a long-awaited Avengers movie.

The Incredible Hulk was already a part-reboot, part-sequel of Ang Lee's 2005 film The Hulk with an entirely new cast. The second iteration of the Hulk movie was a moderate success at the box office. But Universal Studios held—and continues to hold—the distribution rights for any Hulk solo films, so Marvel Studios scuttled plans for a sequel and recast star Edward Norton with Mark Ruffalo for future Avengers team-up films. Ruffalo went on to appear in eight MCU films.

Read More: Breaking Down the Captain America: Brave New World End-Credits Scene

Because of the recasting, Marvel has largely ignored The Incredible Hulk's existence—until now. Captain America: Brave New World is—rather unexpectedly—a direct sequel to the 17-year-old film. The main antagonist in Brave New World is Samuel Sterns, a character who appears briefly in The Incredible Hulk. Moviegoers who have never seen the Norton movie—or watched it so long ago they forgot the plot—may be confused about who Sterns is, why he hates MCU character Thaddeus "Thunderbolt" Ross, and why Liv Tyler makes a cameo at the end of the movie.

Here's everything you need to know about The Incredible Hulk and how it connects to the fourth Captain America film.

What happens in The Incredible Hulk

Dr. Bruce Banner (Norton), with the help of his scientist love interest Dr. Betty Ross (Liv Tyler) submits himself to an experiment involving gamma radiation. Things go awry and Bruce turns him into a big, angry, green monster. Betty's father General Thaddeus "Thunderbolt" Ross (William Hurt) wants to replicate the technology and weaponize it, so Bruce runs away.

Bruce learns to meditate in an attempt to control the monster within while simultaneously trying to create a cure in consultation with a mysterious "Mr. Blue" online. General Ross recruits a soldier named Emil Blonsky (Tim Roth) to hunt Bruce down. To aid Blonsky in his mission, Ross doses Blonsky with a version of the supersoldier serum.

Bruce reunites with Betty to retrieve data about the original experiment in hopes that if helps with an antidote. General Ross and Blonsky attack Bruce on Betty's campus. Bruce transforms into The Hulk and saves Betty's life from her own father who inexplicably has ordered soldiers to shoot in her direction. Betty and Bruce escape and, in an interlude, find out that the Hulk can't get too excited in...umm...any context.

Betty and Bruce travel to New York City to meet with Dr. Samuel Sterns, a.k.a. Mr. Blue. But Sterns turns out to be a bit of a psycho and uses gamma radiation to help Blonsky become The Abomination, an even bigger, angrier monster. Crucially, Sterns also gets hit with a dose of Bruce's blood. The Abomination goes on a rampage in Harlem, and Bruce turns himself into the Hulk to defeat him. Bruce goes into hiding again. Betty swears to never forgive her father for targeting Bruce.

After ignoring it for years, the MCU started referencing The Incredible Hulk again

The Incredible Hulk was all but erased from the MCU timeline, in part because of the decision to recast Bruce Banner. Ruffalo's Bruce, for instance, never brought up the events of that film or his character's love interest, Betty.

For a long time, Hurt, who played General Thaddeus "Thunderbolt" Ross, was the only actor from The Incredible Hulk to appear in other MCU movies. He became an antagonist to Captain America and his allies in Captain America: Civil War. Strangely, Ruffalo's Bruce and Hurt's Ross never confront one another about their past in any of the Avengers films.

Shang-Chi changed the MCU's relationship to The Incredible Hulk when it resurrected Hulk antagonist The Abomination. And She-Hulk, a tongue-in-cheek Disney+ series, frequently referenced the events of The Incredible Hulk. That opened the door to other characters from the film returning for Captain America: Brave New World.

Dr. Samuel Sterns shows up as the villain in Captain America: Brave New World

At the beginning of Brave New World, we learn that General Ross has been elected President of the United States. (Harrison Ford has been recast as the character after Hurt passed away in 2022.) President Ross hopes to get multiple nations to sign a treaty agreeing to split the recently-discovered element of Adamantium, which diligent Marvel fans may remember is the metal used in Wolverine's skeleton and claws. But someone is out to undermine the treaty and embarrass the president.

Though Giancarlo Esposito's Sidewinder has been portrayed in trailers as the main villain of Brave New World, Tim Blake Nelson's Samuel Sterns from The Incredible Hulk turns out to be the mastermind behind the big plot. In a backstory-heavy monologue, Sterns reveals to Captain America (Anthony Mackie) and Falcon (Danny Ramirez) that when he was exposed to Bruce Banner's blood in The Incredible Hulk via a cut on his head, his brain was warped and became massive. He has to live with a morphed, enlarged head and green skin, but he gained the ability to calculate the probability of anything.

Ross—who spends most of the movie yelling at anyone who will listen that he is a changed man since his days of blowing up college campuses—has apparently been keeping Sterns prisoner for 17 long years and using him as his personal mad scientist to develop weapons for the military. Ross also forced Sterns to invent a medication that would keep Ross' life-threatening heart condition at bay. Unbeknownst to Ross, Stern dosed the heart medication with gamma radiation. Sterns then spends much of the movie trying to antagonize Ross and get him to hulk out on live TV.

Sterns' ability to calculate probabilities turns out to be kind of a lame superpower. Sterns seems actively upset any time that an event he estimates has a 20% or less of occurring does transpire, which suggests he doesn't actually understand how statistics work. Sterns is arrested at the end of the film.

Liv Tyler makes a cameo as Betty in Captain America: Brave New World

Throughout the movie, President Ross bemoans the fact that his daughter Betty never forgave him for hunting down Bruce Banner like a fugitive and—this part goes unsaid but surely is part of her fury—trying to create an army of Hulks.

When Ross turns into the Red Hulk, Captain America eventually talks him down by reminding him of his love for Betty. Ross turns himself in for his crime and is imprisoned on The Raft, a floating maximum-security prison. In the final scenes of the film, Liv Tyler's Betty visits her dad and forgives him for everything he has done.

Will this open up an opportunity for Betty to reunite with the (recast) Bruce Banner? Only time will tell.

Write to Eliana Dockterman at eliana.dockterman@time.com.