Bumblebee

As the Autobot resistance on Cybertron teeters on the brink of defeat, Optimus Prime (Peter Cullen), the stalwart leader, orders scout B-127 to escape on a solitary mission to Earth. The Decepticons, led by Soundwave (Jon Bailey) and Shockwave (Jon Bailey), intercept the evacuation effort, forcing Optimus to dispatch B-127 in an escape pod, hoping to establish a new base of operations. However, the Decepticon seekers Starscream, Thundercracker, and Skywarp destroy the launch pad during the chaotic retreat.

Cut to 1987, where B-127 (Dylan O'Brien), battered and bruised, crash-lands in California, disrupting a Sector 7 training exercise led by Colonel Jack Burns (John Cena). Initially, Burns views B-127 as a hostile invader and launches an attack, driving the Autobot deep into the forest. It's there that Blitzwing (David Sobolov), a Decepticon who transforms into a red/white McDonnell Douglas F-4 Phantom II, ambushes B-127. When the Autobot refuses to reveal Optimus's whereabouts, Blitzwing mercilessly tears out his voice box and damages his memory core; undeterred, B-127 manages to take down Blitzwing before succumbing to his injuries.

Meanwhile, teenage girl Charlie Watson (Hailee Steinfeld) remains emotionally scarred by her father's passing and resents her mother Sally (Pamela Adlon) for remarrying. As a birthday gift from junkyard owner Hank (Len Cariou), Charlie stumbles upon an old yellow Volkswagen Beetle in the scrapyard, unwittingly activating a homing signal that catches the attention of Decepticons Shatter (Angela Bassett) and Dropkick (Justin Theroux). These shape-shifters are hot on the trail of B-127, whom they claim is a fugitive. Under the guise of peacekeepers, they convince Dr. Powell and Sector 7 to help them capture B-127, despite Colonel Burns' reservations. Little do they know, their actions will set off a chain reaction that will shake the very foundations of Earth.

As Charlie wrestles with the enigmatic Beetle, it undergoes a profound transformation, emerging as amnesiac B-127, whom she affectionately dubs "Bumblebee". Together, they decipher a cryptic message from Optimus Prime, urging Bumblebee to defend Earth in their absence, and a surge of memories begins to resurface. Memo (Jorge Lendeborg Jr.), Charlie's neighbor with feelings for her, becomes privy to this clandestine affair and agrees to keep the truth hidden. However, when left alone, Bumblebee inadvertently wreaks havoc on Charlie's home, triggering an energy spike that piques the interest of Sector 7. As the situation spirals out of control, Charlie's neighbor Sally attributes the destruction to Charlie herself, prompting her to storm off with Bumblebee and Memo in tow, only to be intercepted by Sector 7 and the Decepticons. In a stunning turn of events, Bumblebee is captured while Charlie and Memo are taken back home.

Charlie finally finds solace in expressing her anguish over her father's passing, and makes amends with her brother Otis (Jason Drucker), who assists her in tracking down Burns to the Sector 7 outpost where Bumblebee is being held. Shatter and Dropkick subject Bumblebee to brutal torture, extracting the location of the Autobots from his ravaged mind, revealing that they're on their way to Earth. As Bumblebee lies near-death, they abandon him for the sake of their sinister plans.

Charlie Electro-shocks Bumblebee back to life, reviving his memories and imbuing him with a newfound sense of purpose. With Burns' obstruction and attempts to re-secure Bumblebee foiled, Charlie and her trusty ally embark on a perilous quest to prevent Shatter and Dropkick from contacting the Decepticons through a radio tower at a nearby harbor, utilizing Earth's satellites to summon an armada of Decepticon minions. Meanwhile, Dr. Powell meets his untimely demise at the hands of Dropkick.

Charlie and Bumblebee fight valiantly against Burns' men, who intervene in their mission, but ultimately find themselves saved by Bumblebee as a helicopter crashes nearby. As Shatter becomes enraged and pursues Charlie, Bumblebee delivers a devastating blow to Dropkick with a chain, crippling the Decepticon. With the beacon deactivated, Charlie's determination sets into motion a chain reaction of events that culminates in a flood triggered by Bumblebee destroying a dam wall, crushing Shatter beneath the rubble.

Burns, having undergone a change of heart, allows Charlie and Bumblebee to escape as the army closes in. As they bid each other farewell, Charlie comes to realize the magnitude of Bumblebee's purpose on Earth. With a heavy heart, she says goodbye to her trusty ally, returning to her family.

Bumblebee reunites with Optimus Prime in a forest, renouncing his designation as B-127 and adopting "Bumblebee" as his new identity. As more Autobots arrive through Earth's atmosphere, Charlie finally completes the Corvette she and her father were working on, driving off into the sunset, symbolizing a new beginning.