Ant-Man and the Wasp: Quantumania (2023)

 from Wikipedia: https://en.wikipedia.org/wiki/Ant-Man_and_the_Wasp:_Quantumania

Ant-Man and the Wasp: Quantumania

    

During her days of entrapment in the Quantum Realm, Janet van Dyne encounters an exiled traveler named Kang. In the present day, after the Battle of Earth, Scott Lang has become a successful memoirist and has been living happily with his girlfriend, Hope van Dyne. Scott's now-teenage daughter Cassie has become a political activist, resulting in her having a strained relationship with her father.

While visiting Hope's parents, Hank Pym and Janet, Cassie reveals that she has been working on a device that can establish contact with the Quantum Realm. Upon learning of this, Janet panics and forcefully shuts off the device, but the message is received, resulting in a portal that opens and pulls the five of them into the Quantum Realm. Scott and Cassie are found by natives who are rebelling against their ruler, while Hope, Janet, and Pym explore a sprawling city to get answers.

Hope, Janet, and Pym meet with Lord Krylar, a former ally of Janet's, who reveals that things have changed since she left, and that he is now working for Kang, the Quantum Realm's new ruler. The three are forced to flee and steal Krylar's ship. The Langs, meanwhile, are told by rebel leader Jentorra that Janet's involvement with Kang is indirectly responsible for his rise to power. The rebels soon come under attack by Kang's forces led by M.O.D.O.K., who is revealed to be Darren Cross, having survived his apparent death at Scott's hands.

Aboard Krylar's ship, Janet confesses to Hope and Pym why she wanted nothing to do with the Quantum Realm again; Kang claimed that he and Janet could both escape from the Quantum Realm if she helped him rebuild his multiversal power core. After they manage to repair it, Janet sees a vision of Kang conquering and destroying entire timelines. Kang reveals he was exiled by his own variants out of fear, which drove Janet to turn on him. Outmatched, Janet used her Pym Particles to enlarge the power core and render it unusable. Kang, having regained his powers, eventually conquered the Quantum Realm afterward.

The Langs are taken to Kang, who demands that Scott helps get his power core back or else he will kill Cassie. Scott is taken to the core's location and shrinks down. He is nearly drowned in a sea of variants of himself, but Hope arrives and helps him acquire the power core. However, Kang reneges on the deal, capturing Janet and destroying her ship with Pym on it. After being rescued by his ants, who were also pulled into the Quantum Realm, rapidly evolved, and became hyper-intelligent, Pym helps Scott and Hope as they make their way to Kang. Cassie rescues Jentorra and they commence an uprising against Kang and his army. During the fight, Cassie convinces Cross to turn sides and fight Kang, though he sacrifices his life in the process.

Janet fixes the power core as she, Pym, Hope, and Cassie jump through a portal home, but Kang attacks Scott, nearly beating him into submission. Hope returns and, together with Scott, destroy the power core with a combination of Pym Particles and knock Kang into it, causing him to be pulled into oblivion. Cassie reopens the portal on her end for Scott and Hope to return home. As Scott happily resumes his life, he begins to rethink what he was told about Kang's death being the start of something terrible happening, but brushes it off.

In a mid-credits scene, numerous variants of Kang are concerned by Earth-616's increasing interest in the multiverse and plan their uprising. In a post-credits scene, Loki and Mobius M. Mobius locate another Kang variant, named Victor Timely, on Earth in the 1900s