In a frozen tundra, Kord Industries, led by CEO Victoria Kord, has located an artifact known as the Scarab, which Victoria has been searching for for several years.

Meanwhile in Palmera City, Texas, Jaime Reyes has returned home after graduating from Gotham Law University, where he receives a warm welcome from his family. However, he learns that his family will be losing their home due to financial difficulties stemming from increased rent and his father Alberto Reyes losing his job. Despite this, he is optimistic that he will quickly get a job and make enough money for his family.

A few months later, Jaime is an employee at Victoria’s mansion, working alongside his sister Milagro Reyes. One day, Jaime overhears Victoria being confronted by Jenny Kord, Victoria’s niece, and the daughter of Ted Kord, the previous CEO of Kord Industries. Jenny has learned of Victoria’s plans to release the OMAC (One Man Army Corps) project which her father had shut down years ago. When it seems like Victoria’s bodyguard Ignacio Carapax is about to hurt Jenny, Jaime steps in. Victoria lets Jenny go, but fires Jaime and Milagro. Jenny tells Jaime to meet at Kord Tower the next day, as she may be able to find a job for him. Jaime is nervous, but accepts.

The next day, Jenny finds that Victoria is using the Scarab for her OMAC projects. Jenny places the Scarab in a to-go box, and is about to leave the building. However, as she is doing so, Jaime meets with her and the security alarms go off. Jenny gives Jaime the box to guard, and despite Jenny’s warnings against doing so, Jaime’s family goad him into opening the box. After Jaime touches the Scarab, it activates and attaches to him, creating a suit of armor around Jaime, before flying him out of orbit, then back to Palmera, where the Scarab’s defense mechanisms cause it to slice a bus in half. Jaime goes to find Jenny, who is being attacked by Victoria’s armed forces. After rescuing her, Jenny tells Jaime what she knows about the Scarab, and how it has chosen Jaime to be its host. Jaime wants to remove the Scarab from himself, and Jenny offers to help, but needs a key located in Kord Tower.

Thanks to Jaime’s uncle Rudy, Jaime and Jenny are able to break into Kord Tower easily and grab an old smartwatch. As they leave however, they are stopped by Carapax who has an OMAC protoype infused in his body. The Scarab, revealed to be named “Khaji Da”, temporarily takes over Jaime’s body. After defeating Carapax, Khaji Da attempts to kill him, but Jaime stops it saying he doesn’t want to kill anyone. Jaime gets distracted when Carapax attempts to attack Rudy, allowing Carapax to pin Jaime. However, Rudy and Jenny knock Carapax unconscious, before rescuing Jaime.

Jenny takes Jaime and Rudy to her childhood home, where she uses the smartwatch to open a basement door. After looking around the basement, Rudy realizes that Ted was the Blue Beetle, a hero of Palmera City. Jenny explains that the title of Blue Beetle used to belong to Dan Garrett, an archeologist who found the Scarab, and like Jaime, was chosen by Khaji Da to be its host. Garrett left the Scarab as well as the title of Blue Beetle to Ted. However, Khaji Da never chose Ted, so he built his own technology. After looking through Ted’s notes, Rudy finds that the Scarab’s goal is to become perfectly symbiotic with and protect its host as long as it can and is only removable if the host dies. Jaime wants to live a normal life, but Rudy tells him to embrace becoming a hero.

Jenny warns Jaime and Rudy of Victoria’s helicopter and they see that it is heading towards his home. Jaime triggers Khaji Da to put on the Beetle Armor and heads to protect his family. At the Reyes’ home, Victoria comes with armed forces to capture Jaime. While pulling the Reyes family out, a candle drops, starting a fire in the house. Jaime arrives in time and takes down the majority of Victoria’s forces, but gets distracted when his father starts suffering from a heart attack allowing Carapax to capture Jaime as his father dies. Jenny takes the family back to the Beetle cave where they use an airship to track and get to Victoria’s location.

Meanwhile on an island near Cuba, Jaime is trapped in a machine that is forcibly downloading information from Khaji Da to the OMACs, including the one Carapax is wearing. While unconscious, Jaime sees a vision from his father who tells him that he will be with him, but Jaime needs to embrace the Scarab. Jaime embraces his father before connecting with the Scarab and is able to escape just as Victoria finishes downloading the Scarab’s data. As he escapes, Carapax’s OMAC suit activates, creating a much more powerful form.

As Jaime is escaping, Jenny and the Reyes family storm the island and spread through the tunnels. Jenny and Milagro find the OMAC suits and set explosives to destroy them. As a result, one of the tunnels cave in, causing Milagro and Jenny to become separated, with the latter being found by Victoria.

Meanwhile as Jaime runs through the tunnels, he is cornered by a few guards, unable to use the suit. As they close in on him, Jaime’s “Nana” comes in with a machine gun to save him. After reuniting with Rudy and his mother, Jaime learns that Milagro and Jenny are still missing. Jaime and Rudy go back to find them. After Khaji Da reboots, Jaime finds and rescues Milagro, before being attacked by Carapax, now significantly stronger. Just as Carapax is about to kill Jaime, Rudy distracts him, allowing Jaime to escape. Jaime thinks Carapax killed Rudy and his anger fuels him to subdue Carapax. In his anger, Jaime is about to kill him, but Khaji Da holds him back. Khaji Da reveals that while his data was being transferred, he was able to glance at Carapax’s memories revealing that several events in Carapax’s life were due to Victoria’s actions. Jaime spares Carapax as he reunites with Jenny, who destroyed Victoria’s helicopter as well as all the data she had on the Scarab. Despite the island exploding around them, Victoria demands Carapax kill Jenny. However, Carapax, tired of her orders, drags Victoria to the center of the island as he sets his OMAC suit to explode.

A few days later, while Jenny takes over Kord Industries, the Reyes family return home from mourning Alberto’s death. As they look at their burned house, their neighbors come by, bringing food and offering support to help rebuild their house. Jenny tells Jaime that she is going back to her old house, and Jaime offers to use the Blue Beetle suit to fly her there.

During the credits, Ted sends a message to the Beetle cave telling that he is still alive.