Godzilla vs. Kong (2021)

The year is 2024. Five years have passed since Godzilla killed his extraterrestrial nemesis Ghidorah in 2019, while he and Kong are currently the only active Titans on Earth. On Skull Island, its climate has become unstable due to a storm generated by Ghidorah combining with the storm cell perpetually surrounding the island, forcing Monarch to contain Kong inside a dome-shaped facility that simulated the island's environment, with an orphaned young Iwi named Jia, who is deaf and can communicate with Kong via sign language, providing him company. However, Kong found out about the biodome and immediately threw a tree at it.

Meanwhile, Bernie Hayes, an employee of the Apex Cybernetics corporation and host of a Titan conspiracy theory podcast known as the Titan Truth Podcast, exfiltrates information suggesting sinister activities at a Pensacola Apex facility, but Godzilla suddenly attacks the facility. During the rampage, Bernie discovers a cybernetic eye with a device inside, similar to the ORCA that was used by the late Emma Russell to communicate with and control Titans. In the aftermath of the attack, public opinion has turned against Godzilla, who is no longer viewed as humanity's savior. Madison Russell, now a young adult and a fan of Bernie's podcast, sees the news about Godzilla's recent attack and is worried. She tries to convince her widowed father Mark Russell, acting as Monarch's director, that Godzilla is being provoked, but Mark dismisses his daughter's belief in the Titan Truth Podcast and only replies that creatures, just like people, can change. Later, Madison enlists the help of her friend Josh Valentine to investigate the one behind Godzilla's rampage so that they can clear his name.

Together, they find Bernie, who joins their investigation. They sneak into the wrecked Apex base and discover a secret facility deep underground, but are inadvertently locked and transported in an antigravity transport vehicle carrying Skullcrawler eggs through an underground tunnel to Hong Kong. There, they unwittingly intrude on a test of Mechagodzilla, a robotic counterpart of Godzilla piloted by Ren Serizawa, son of the late Ishiro Serizawa using the skull of Ghidorah's left head that Apex had managed to retrieve after it was previously bitten off by Godzilla and purchased by Alan Jonah five years ago. Mechagodzilla was used in a test to kill a large Skullcrawler codenamed "Number 10" by slicing it in half using its proton scream while Madison, Josh and Bernie seek shelter in a bunker, but the test is however cut short due to limitations of the power supply. It's then revealed that Apex's founder and CEO Walter Simmons intends to harness the power of a powerful energy source in the Hollow Earth, an underground world below the Earth and the hidden home to the Titans, to overcome Mechagodzilla's limitations.

Walter recruits Nathan Lind, a former Monarch scientist turned Hollow Earth theorist, to help guide them to the Hollow Earth in search of the energy source. Nathan is initially hesitant since his brother tried to explore the Hollow Earth, but a strong anti-gravity field inside the tunnel killed him. He agrees after Walter reveals that Apex has developed Hollow Earth Aerial Vehicles, specialized crafts to withstand the gravity field's pressure. To help guide them to the Hollow Earth, Nathan travels to Skull Island and meets Monarch anthropological linguist and Jia's adoptive mother Ilene Andrews with his idea of using Kong as their navigator to lead them to the energy source since Skull Island is no longer able to contain him (because Kong has grown too large) and allow him to survive. Though Ilene rejects this at first as she explains that Godzilla would come for Kong as soon as he was moved off of Skull Island, she finally accepts after Nathan convinced her that they need to undertake this mission in order to stop Godzilla and that they can also find Kong a new home.

Nathan, Ilene, Jia, and an Apex team led by Walter's daughter Maia board a modified barge with Kong chained and lightly sedated. One rainy night, an agitated Kong starts to pull on the chains restraining him, though Jia calms him down by allowing her and Kong to touch fingers in solidarity before Kong signs the word "home", much to everybody's amazement. The next day, Ilene explains to Nathan on how she raised Jia as her adoptive daughter after dangerous and unpredictable storms wiped out most of the Iwi and her parents, but Jia herself was the sole survivor since Kong was the one who protected her, leading to the two forming a bond and kinship. At this point, Jia senses Godzilla, who arrives and suddenly attacks the military by slicing a ship in half and smashing several planes with his tail. Nathan frees Kong, who starts to battle Godzilla, but he is able to defeat the Titan by nearly drowning him. However, their fight is broken up by depth charges and the ships shut down their power to trick Godzilla into thinking he destroyed them and Kong was defeated. The plan succeeds and Godzilla eventually leaves. Realizing that Godzilla could return if they reactivate the ships, they change plans and instead fly Kong to a Hollow Earth entry point in Antarctica where Ghidorah was originally frozen. There, Kong refuses to go even with Jia's insistence. Instead, Nathan and Ilene suggest telling Kong that his kind could possibly be down there, prompting him to enter the tunnel, and the teams follow him in the HEAVs. Meanwhile, Mechagodzilla begins sending a signal to Godzilla, who senses the machine's activation and heads straight towards Hong Kong.

Inside the Hollow Earth, Nathan's team find an ecosystem similar to Skull Island. While traversing the landscape, they are attacked by a pair of Warbats, but Kong manages to kill both of them. After the fight, Kong and Nathan's team make their way to an ancestral throne room belonging to Kong's species, where they find remains of an ancient war with Godzilla's kind while Kong notices a glowing axe made from a dismembered dorsal plate of another member of Godzilla's race. As Nathan's team discover the power source they need to increase Mechagodzilla's power supply, Kong learns that the same power source can recharge the axe. However, Maia and the Apex team use drones to send the power source's signature back to their Hong Kong base, despite Ilene's protests. Meanwhile, Godzilla makes landfall in Hong Kong and sensing Kong, drills a hole into the Hollow Earth with his atomic breath, causing the temple to collapse. Kong avoids Godzilla's atomic breath and fights off a flock of Hellhawks while Maia and her team try to abandon Nathan's team and escape, only for Kong to crush their HEAV on their way out, killing Maia and her personnel inside. Kong, Ilene, Jia, and Nathan escape through the hole to Hong Kong, where Kong fights Godzilla again. Kong sees that his axe can harness Godzilla's atomic breath and releases it to seemingly beat Godzilla, with the resulting shockwave knocking Godzilla unconscious, but he recovers and resumes the fight. The fight ends with Godzilla overpowering Kong and dislocating his left arm before roaring in his face to submit. However, Kong responds by roaring back at Godzilla in defiance, showing that he refuses to submit. As if impressed by this show of defiance and bravery, Godzilla spares his opponent's life and leaves as Kong loses consciousness.

Back in the Apex base, Walter orders Ren to send Mechagodzilla out to kill Godzilla, though Ren warns him against using the new Hollow Earth energy source without testing, but Walter ignores his pleas. Meanwhile, Bernie, Madison, and Josh are caught red-handed by security and taken to Walter. Madison accuses Walter of provoking Godzilla into war and for causing all of this, though he confidently explains that he accepted the responsibility for giving mankind a chance to fight back against Godzilla and the Titans so that humans can remain the dominant species. Unknown to Walter as he monologues about his creation, Mechagodzilla suddenly goes haywire under the influence of both the energy source and Ghidorah's neural networks, resulting in Ren's death by electrocution and Walter being crushed by Mechagodzilla's hand. Mechagodzilla, now possessed by Ghidorah's consciousness, emerges from the Victoria Peak's base and rampages through the city before Godzilla confronts it. Quickly coming into contact with Godzilla, Mechagodzilla assails its organic counterpart with missiles before the two begin their battle.

While Josh unsuccessfully tries to shut down the rampaging robot remotely, Godzilla and Mechagodzilla battle, at one point firing both their energy beams at each other which lock together, only for Mechagodzilla to gain the upper hand, knocking Godzilla over and severely burning him. While Mechagodzilla continues to overwhelm Godzilla, Nathan, Ilene, and Jia approach an unconscious Kong, where Nathan revives him by detonating the remaining HEAV on Kong's chest to act as a defibrillator, saving him. After Kong awakens, Jia convinces him that Godzilla is not the enemy, though Kong has no interest and refuses to believe her at first until Jia shows him Mechagodzilla and tells Kong that this is the "real" enemy, prompting the Titan to reset his dislocated arm and head into battle. As Mechagodzilla prepares to fire its proton scream down Godzilla's throat, Kong leaps onto the robot and redirects the beam into the air, saving Godzilla's life in the process. Realizing that Kong saved his life and having found a new ally, Godzilla helps Kong fight against Mechagodzilla, but the robot puts the two Titans at its mercy, with the mecha having its tail almost drill into Kong. However, Josh short-circuits Mechagodzilla's controls by pouring Bernie's flask of liquor, causing the robot to pause for a second just long enough for Godzilla and Kong to recover. Seeing Kong holding his axe, Godzilla supercharges it by blasting the weapon with his atomic breath, allowing Kong to slice off Mechagodzilla's limbs and tail and finishing off the mecha by tearing off its head before slumping down from exhaustion.

In the aftermath, Madison reunites with Mark and introduces him to Josh and Bernie, with Bernie asking if he can invite Mark on his podcast sometime. Suddenly, their moment is interrupted when Godzilla roars, drawing Kong's attention. Kong grabs his axe and prepares to confront his rival again, but Godzilla instead shows no interest in fighting anymore and merely stares Kong down. In response, Kong lets his axe fall to the ground, ending the many millenniums of conflict between his and Godzilla's race. Godzilla roars in acknowledgement and respect for Kong, seeing him as an equal and a friend (same with Kong respecting Godzilla as an equal and a friend) before returning to the sea and disappearing beneath the waves as Kong and the gathered humans watch on, safe in the knowledge that the world is finally at peace.

Sometime later, Monarch have created an observation post in the Hollow Earth. Ilene, Nathan and Jia watch as Kong passes by on his morning walk. After signing "home" to Jia, Kong beats his chest and bellows, proclaiming himself as the King of the Hollow Earth and accepting it as his new home and kingdom.