Transformers 6 : Rhythms of Darkness

Transformers 6 : Rhythms of Darkness is a 2023 science fiction action film which serves as the sixth instalment in Hasbro's Transformers live-action movie franchise and a sequel to 2017's Transformers: The Last Knight.
Plot
Billions of years ago, the planet-devouring dark god Unicron terrorizes the universe and is opposed by the pantheon of deities known as the Guiding Hand consisting of Primus, the God of Light and Order, followed by the deities Epistemus, Solomus, Mortilus and Adaptus. On the planet Cybertron, Primus brings forth the Guiding Hand from his own essence in response to the emergence of the Chaos-Bringer Unicron, his opposite. Primus and the Guiding Hand are able to defeat Unicron and cast him out into the depths of space. The pantheon then gives rise to a new generation of life on Cybertron, establishing civilizations on the planet and ushering in a golden age of peace and prosperity. The peace comes to an end with the outbreak of the God War where Mortilus urges the Guiding Hand to wage war against the galaxy to prevent stagnation of the Cybertronian race. The pantheon perishes in the God War after being reduced into each of their most basic essences: Vector Sigma, the brain module, the transformation cog and the AllSpark. Primus's essence is concentrated into the AllSpark after he dies vanquishing Mortilus. Eons later, from the essence of the fallen gods in the depths of Cybertron emerges the goddess Quintessa who discovers the AllSpark. Quintessa forges a staff to manipulate the AllSpark's life-giving energies in order to give life to a race of sentient machines known as the Transformers whose bodies are forged with metals harvested by cyberforming other worlds. The Transformers are forged because Quintessa is obsessed with creation and wishes for the genesis of new civilizations on Cybertron which she desires to transform into the crown jewel of the galaxy. The Quintessons are a techno-organic race created as subjects for Quintessa who use devices called the Seeds to cyberform entire worlds and use the metals generated to build the Transformers. The first generation of Transformers consist of twelve beings known as the Knights of Cybertron. Over time Quintessa grows corrupt with her powers of creation and decides to use the galaxy as her personal laboratory for her experiments in creating life. She discovers that the monstrous Unicron's resting point is the planet Earth, one of the many worlds previously visited and cyberformed by the Quintessons. Quintessa plans to drain the very life from Unicron, despite planet Earth being inhabited, in order to secure a political advantage and proclaim herself as the saviour of Cybertron who would vanquish the Chaos-Bringer for good. When the Knights discover her dark designs, they betray her and steal her staff, sparking a planet-wide rebellion in which the Transformers rise up against their Quintesson masters and drive them off-world. Quintessa is banished from Cybertron by her own creations. The Knights of Cybertron then unite the AllSpark with Vector Sigma at Cybertron's core, which is supposedly the creator god Primus, allowing hot spots to ignite across the planet and giving rise to new generations of Transformers who have no recollection of prior events. The first of these new Cybertronians are the seven Primes. The Dynasty of Primes believes the AllSpark to be the creator of their race and employ machines known as the Star Harvesters to recharge the AllSpark with the power of stars. The Dynasty rules Cybertron and protects the AllSpark till they are betrayed by one of their own. The Primes believe that all life is sacred and refuse to harvest the energy of stars orbited by inhabited worlds, but this rule is challenged by one of the Primes when they arrive on Earth, the third planet orbiting the star Sol. The seventh Prime wages war against his six brothers for the fate of Earth and humanity; for his betrayal the renegade Prime is thereafter known as the Fallen. The war among the Primes on Earth sets in motion the events that would lead to the Great War on Cybertron fought between Optimus Prime (apprentice of Sentinel Prime) and Megatron (apprentice of the Fallen) over the AllSpark. Ultimately the AllSpark was lost in space and Cybertron was left barren due to the war between Autobots (led by the noble Optimus Prime) and Decepticons (led by the tyrannical Megatron). The war between the Transformers eventually found its way to planet Earth and the intertwined history of Cybertron and Earth was gradually unravelled.
In the present day after Cybertron arrived in Earth's orbit, Optimus Prime and the Autobots rebuild a war-torn Cybertron while monitoring the casualties due to Cybertron colliding with Earth. Quintessa's staff of creation is used to stabilise Cybertron so that its gravitational force does not tear Earth apart. Meanwhile Unicron's horns begin to rise from Earth's crust triggering natural disasters on Earth, prompting several hidden Decepticons to resurface from hiding to escape the crisis. As Optimus Prime scans the planet to find his nemesis Megatron who is still at large, the Autobots Drift, Crosshairs and Grimlock along with Colonel Lennox and his troops are tasked with hunting down the rogue Decepticons before they endanger humans. Elsewhere, the Decepticon Barricade helps repair his battle-damaged leader Megatron who is stranded on Earth and has lost an arm in his previous duel with Optimus Prime. Drift and Crosshairs battle the Decepticons Oil Slick and Lugnut and report back to Optimus about a string of human kidnappings and the emergence of undead zombies known as Terrorcons across the planet. A Terrorcon attacks and bites Barricade before it is neutralized by Megatron, who claims that there are no more voices in his head and that he is no longer a puppet with strings on him. On their Earth base, Bumblebee talks with Optimus expressing regret for leaving their old human ally Sam Witwicky behind when the Autobots were being pursued by Lockdown. Bumblebee later plunges into regret when he discovers that Sam has died by this point, driving off to his grave in Washington, D.C. and is followed by Hot Rod. Bumblebee confides in Hot Rod his feelings for Sam and they have a conversation about their early days on Earth, including their participation in World War II. Subsequently they are confronted by Barricade and Megatron. Bumblebee and Barricade engage in a rematch before Barricade collapses in pain and slowly dies as his spark gets depleted of power. Megatron asks the Autobots for an audience with Optimus, proposing an alliance against Unicron. 
Sometime later Optimus Prime, Hound, Drift, Crosshairs, Ultra Magnus, Springer and Topspin storm a military base in Africa where Quintessa in her human disguise has been brainwashing kidnapped humans into rebuilding a space bridge. After fighting hordes of Sharkticons, Quintessa is taken prisoner by the Autobots and incarcerated in a fortress on Cybertron. Before Quintessa can be interrogated, Optimus Prime receives a transmission from Bumblebee and Hot Rod who inform him that Megatron wants to talk. A furious Optimus Prime and his lieutenant Ultra Magnus set out to confront Megatron, who declares that his last death has put matters into perspective. Now that he is free from Quintessa's command, Megatron claims that he is renouncing his ways of oppression with no desire to inflict it upon anyone else again, and that Quintessa has manipulated the war between Autobots and Decepticons for her own gain. Optimus is reluctant to trust him before Megatron brings up their shared history on Cybertron before the war when they ruled as brothers under the mentorship of Sentinel Prime. Megatron is now only interested in rebuilding Cybertron after the damage done due to eons of war, and reveals how he didn't backstab Optimus before the war when he had the opportunity because he knew that Cybertron needed his leadership, instead becoming his brother-in-arms and training him to be a great warrior. After being convinced by Hot Rod and Bumblebee to hear Megatron out, Optimus Prime converses privately with Megatron as the two reminisce about their past on Cybertron and contemplate the unfathomable mysteries of the universe, with Optimus acknowledging that Megatron's death did not bring him any peace. Crosshairs arranges for the Knights of Cybertron to return to Earth for a meeting with Optimus Prime. The Knights divulge the truth behind the creation of the Transformers to all those present, hoping to grant them a peace of mind in order to arrive at a solution to the impending crisis of Unicron's awakening. Optimus Prime realizes that Lockdown told him a fabricated tale of his creators with Megatron noting that Lockdown was a bounty hunter who was interested only in material gain and was hence easily swayed by Quintessa, who returned to Cybertron following the destruction of the AllSpark and the battle in Chicago. The Knights of Cybertron recount that Unicron was defeated the first time by Primus and his brethren, the Guiding Hand, and that the AllSpark, being the very essence of Primus himself, is the only way to force Unicron back into stasis without endangering the Earth. When Optimus Prime reveals that the AllSpark Cube was destroyed in Mission City, the Knights reveal that the AllSpark was in fact not destroyed but continues to reside within Optimus's chest as the Matrix of Leadership. Bumblebee realizes that the power and knowledge of the AllSpark transferred to Sam Witwicky's mind and then to the Matrix of Leadership, replacing the Cube as its physical form. Suddenly an earthquake strikes and Unicron manifests on the surface of Earth as a stone avatar, which attacks the Cybertronians but is vanquished by their combined might. Megatron teams up with the Autobots to concoct a plan to use the Matrix of Leadership against Unicron. 
The Autobots and Knights return to Cybertron along with Megatron to resume their interrogation of Quintessa. Now a shell of her former self left with only a fraction of her powers, Quintessa reveals that she hypnotized the human slaves to retrieve Sentinel Prime's space bridge pillars from the now defunct KSI as a means to travel to the Earth's core where Unicron's Anti-Spark chamber lies. Back on Earth, several more of Unicron's stone avatars emerge and start wreaking havoc. In desperation, Optimus opens the Space Bridge to Earth and assigns Bumblebee, Hot Rod and Topspin to retrieve the control pillar safely stored in the late Sir Edmund Burton's Castle Folgan (which is now overseen by Cogman). Bumblebee, Hot Rod and Topspin arrive to see the castle under siege by Terrorcons and assist Cogman and the veteran Autobots stationed at the castle in fighting them off. Cogman, now serving as the head of a larger Cybertronian body, explains that a Terrorcon bite can infect a Transformer's energon and cripple them culminating in a painful death (Bumblebee realizes what happened to Barricade). Cogman agrees to give the Autobots the space bridge control pillar. Simultaneously Optimus Prime, Megatron, Ultra Magnus, Springer, Hound and Grimlock go to Earth aboard the Knights' Temenos to combat Unicron's stone avatars in the Grand Canyon. A giant stone avatar emerges and is only defeated by the combined firepower of the entire ship's weaponry. Realizing that they will be outmatched and outnumbered by Unicron's avatars, Optimus Prime sets course for Chicago and retrieves the bodies of many Autobots and Decepticons that fell in the Great War and were salvaged by KSI. The bodies are taken back to Cybertron where Quintessa is coerced into rebuilding them with her staff and a Seed. Thus the Autobots Ironhide, Ratchet, Jazz, Arcee, Jetfire, Dino/Mirage, Sideswipe, Leadfoot, Roadbuster, Que/Wheeljack and Sentinel Prime are resurrected along with the Decepticons Starscream, Soundwave, Blackout, Brawl, Shockwave, Bonecrusher, Mixmaster, Onslaught, Nitro Zeus, Scorponok and Barricade. After Bumblebee, Hot Rod and Topspin return to Cybertron with the control pillar, the Space Bridge is triangulated to transport Optimus Prime, Megatron, Bumblebee, Ultra Magnus and Hot Rod to Earth's core while the resurrected Autobots and Decepticons along with the Knights of Cybertron pilot Orbital Assault Carriers to come to the defense of Earth against the Terrorcons and Unicron's stone avatars (alongside the Autobots and Knights saving humans from natural disasters brought about by Unicron slowly awakening).
Inside Unicron, the team of Optimus Prime, Megatron, Bumblebee, Ultra Magnus and Hot Rod fight their way through swarms of Terrorcons to reach Unicron's Anti-Spark chamber. Optimus tries to open the Matrix but is shackled by Unicron's dark energy. Megatron then picks up Optimus Prime's Sword of Judgement, supercharges it with the Matrix and plunges it into Unicron's Anti-Spark, allowing Optimus to break free from Unicron's restraints and open the Matrix of Leadership to light their darkest hour, sending Unicron's Anti-Spark into stasis. The Terrorcons stop dead in their tracks, Unicron's avatars crumble and the natural disasters on Earth's surface come to a halt. With Unicron sent back into slumber, the Earth settles. The team bridges out of the Earth's core and appear to be successful in preventing the Chaos-Bringer from rising and wiping out all life on Earth. The rest of the Autobots and Decepticons return to Cybertron while Optimus Prime and Megatron reflect on the tranquility that Earth will enjoy as Cybertronians are departing Earth for good to rebuild their war-torn planet. With Optimus and Megatron agreeing to a truce, the Great War is over. The Autobots and Decepticons will lead Cybertronian civilization to a new era of peace and prosperity after a lifetime of war. Back on Cybertron where planetary engines are being constructed to move Cybertron out of Earth's orbit, Optimus Prime gives a speech addressing the assembled Autobots and Decepticons and sends a message ushering in a new golden age of peace and unity, rejoicing that the day has come at last when all are one.