- "This is S.H.I.E.L.D., we're here to help. We have an aircraft to evacuate any civilians trapped near the center of the city. You'll know it when you see it. Get them there. We will clear the high floors of the impacted buildings before they collapse. And most importantly, do not engage the enemy. I repeat, do not engage the enemy. We will handle it."
- ―Alphonso Mackenzie[src]
The Battle of Chicago was the final confrontation between S.H.I.E.L.D. and an unhinged Glenn Talbot, in order to stop him from infusing himself with the Gravitonium located under Chicago and bringing about the Destruction of Earth.
Talbot had previously infused himself with mined Gravitonium to end the Siege of the Lighthouse with the intent of atoning for his mistakes when kidnapped by HYDRA, but he became drunk with power and convinced that he needed to augment his powers in order to face Thanos. Directed to Chicago by the Inhuman seer Robin Hinton, he began to destructively mine the Gravitonium he felt he required. As S.H.I.E.L.D. evacuated the city on Zephyr One, Quake subdued Talbot and attempted to appeal to his patriotism, but he was by this point too far gone and attempted to absorb Quake herself for her powers.
Initially, Talbot succeeded in absorbing Quake and used her powers to cause earthquakes in order to mine Gravitonium, inadvertently cracking Earth into pieces, which left those on Zephyr One as the last survivors of humanity while Alphonso Mackenzie was killed trying to save Polly Hinton. However, Phil Coulson and Leo Fitz successfully rewrote the timeline when Coulson supplied Quake with the Centipede Serum intended to save his life while Fitz saved Mackenzie and Hinton, sacrificing his life in the process. Injecting herself with the serum, Quake freed herself and ejected Talbot into space, killing him and averting the planet's destruction.
Upon being captured by HYDRA, General Glenn Talbot was subjected to the Faustus method, which led him to disclose sensitive information about S.H.I.E.L.D.. Talbot was eventually released thanks to S.H.I.E.L.D. and brought back to the Lighthouse, where S.H.I.E.L.D. also stored some Gravitonium they had confiscated from HYDRA. In an attempt to redeem himself for his past mistakes, Talbot infused himself with the Gravitonium, which granted him gravity manipulation abilities. Thanks to that, Talbot was able to put an end to the Siege of the Lighthouse conducted by the extraterrestrial alliance known as the Confederacy.
However, Talbot soon began to display an extreme megalomania because of his powers which came with mental instability due to his former condition. As a result, Talbot, who was convinced that he was the only hero able to stop Thanos' invasion, seized a seat in the Confederacy and decided to find more Gravitonium so that his powers would be even greater. Facing Hale's and especially Phil Coulson's disapproval, Talbot turned against his former friend. He murdered Hale and ordered Coulson and his S.H.I.E.L.D. allies to be taken prisoners while he would search for more Gravitonium, despite S.H.I.E.L.D.'s attempt to stop him.
In order to locate the untapped deposits of Gravitonium, Talbot kidnapped the Inhuman Robin Hinton and her mother Polly. Then, he forced Robin to disclose the location of a Gravitonium deposit located underneath the city of Chicago.
Glenn Talbot took the remnants of Qovas' Ship and crashed it into the city of Chicago, where he could find more Gravitonium according to Robin Hinton. Talbot then left the spaceship, leaving Robin and Polly Hinton guarded by two Remorath soldiers. The spaceship's crash damaged buildings in Chicago, prompting the authorities to send first responders to get civilians to safety.
Talbot located an underground deposit of Gravitonium and began extracting it using his powers. To that end, he lifted a column of rock out of the streets of Chicago until he could access the Gravitonium stuck to the rock. Once he found it, Talbot absorbed the element before letting the column fall on the ground, causing more damage in the city.
While Chicago Police Department Officer Zbyszewski prepared to engage Talbot, S.H.I.E.L.D. soon intervened in an attempt to stop Talbot. They took the Zephyr One to Chicago and contacted the civilians and first responders, instructing them to evacuate to the Zephyr and to not engage with Talbot. While Jemma Simmons, Yo-Yo Rodriguez and Piper remained in the Zephyr One to coordinate the evacuation, Alphonso Mackenzie, Melinda May and Leo Fitz went to search the damaged buildings to rescue trapped inhabitants.
Fitz, Mackenzie, and May soon found Robin, who had escaped from the crashed spaceship. However, her mother Polly was still trapped in the remnants of the spacecraft, prompting Mackenzie to board the ship to and find her. Fitz remembered that neither Mackenzie nor Polly were alive in the future, so Fitz and May decided to go into the spaceship as backup. As he released Polly, Mackenzie was attacked by the two Remorath guards. He held them off until May and Fitz arrived from behind and killed them.
Meanwhile, James Davis flew a Quinjet with Phil Coulson and Quake into the city. Although Quake planned to neutralize Talbot so Coulson could talk him down, Coulson revealed that he would not join the battle as he was too weak to stand, as he hadn't taken the Centipede Serum cure. Coulson and Quake had a brief argument, but Coulson convinced Quake to go and confront Talbot on her own. Quake reluctantly agreed and left the Quinjet, ordering Coulson to return to the Zephyr One and take the remedy. Actually, she was unaware that Coulson had hidden the syringe containing the cure within her gauntlets.
Davis flew the Quinjet back to the Zephyr One. Upon realizing that Coulson had lost consciousness due to his illness, he took him to his colleagues. Rodriguez performed chest compressions on him while Simmons left to fetch the syringe, only to find that it was gone. Rodriguez was able to revive Coulson.
Quake ran through the streets of Chicago to find Talbot. Using her Inhuman powers, she flew into Talbot, and they crashed into a bus. Quake ordered Talbot to stop because he was killing people. Talbot replied that they were collateral damage and that he had to boost his power so he could defend the Earth. Quake appealed to Talbot as a military man and a father, telling him he was already a hero from having sworn to protect his country and that he could do it without frightening his own son.
At first, Talbot appeared moved by Quake's speech. However, he associated Quake's words with the speeches Hale had given him before torturing him and to what Coulson had said to him before acting behind Talbot's back. Talbot grabbed Quake and flew into the sky with her. He then violently crashed Quake back onto the ground, causing a powerful shockwave which caused rubble to collapse on Fitz in a nearby building where he, Mackenzie, May and the Hintons were.
Talbot forced the weakened Quake to stand and decided to absorb her so that he could use her powers to access the Gravitonium more easily. As Quake was on the verge of being absorbed, she discovered the Centipede Serum that Coulson had placed in her gauntlets. She injected herself with the serum, which instantly gave her the strength to break free from Talbot. Enraged, Talbot attacked her one last time, but Quake used her enhanced powers to blast Talbot into space, killing him.
Meanwhile, May and Mackenzie cleared the rubble covering Fitz. They discovered that he was seriously wounded, having been sliced through the middle by a piece of corrugated metal. Realizing that there was nothing they could do, May and Mackenzie remained at Fitz's side, crying and holding his hand as Fitz struggled to breathe. Mackenzie spoke reassuringly to Fitz, trying to keep him calm until he died from his wounds.
Altering the Timeline
Thanks to Phil Coulson refusing to take the Centipede Serum to save his own life, Quake was able to defeat Glenn Talbot and avert the Destruction of Earth. S.H.I.E.L.D. saved humanity from the bleak future they had witnessed. The destruction of Earth and all the subsequent events they had experienced became an alternate timeline which was prevented by Coulson's selfless action.
Despite Leo Fitz's death during the battle, the S.H.I.E.L.D. agents, and especially Jemma Simmons, figured out that there was still a version of Fitz out there in the universe somewhere. Because he had been left behind when the rest of the team was abducted by Enoch, Fitz used a Cryo-Freeze Chamber to be put into suspended animation where he would remain for seventy-four years to join his friends in the future. When the S.H.I.E.L.D. agents returned from the future, it was after Fitz had frozen himself, which meant that he should still be alive in his space capsule. They decided to find him and to bring him back to Earth.
After the success of the S.H.I.E.L.D. mission to save the Earth, and knowing he had only days or weeks to live, Coulson decided to retire from S.H.I.E.L.D. in the aftermath of the battle. Coulson and Melinda May went to Tahiti while the other S.H.I.E.L.D agents, now led by Alphonso Mackenzie, carried on their new missions.
Originally, the Centipede Serum was used on Phil Coulson to save his life. As a result, when Quake confronted Glenn Talbot, she was overpowered and Talbot used his Gravitonium-based physiology to absorb her, thus acquiring Quake's powers. Using these new vibration manipulation abilities, Talbot quaked the ground in order to access the Gravitonium he desired. By doing so, he caused massive earthquakes, including an extremely powerful one which reached magnitude 12.8 on the Richter scale. This caused the Earth to crack apart and it was ultimately destroyed.
Melinda May flew the remaining S.H.I.E.L.D. agents and the citizens of Chicago to the Lighthouse. However, the planet's destruction caused massive casualties and only a small fraction of humanity survived the global cataclysm. Among the many victims were Polly Hinton and Alphonso Mackenzie. Having lost her mother in the cataclysm, Robin Hinton was adopted by May.
- Agents of S.H.I.E.L.D.: 5.15: Rise and Shine
- Agents of S.H.I.E.L.D.: 5.17: The Honeymoon
- Agents of S.H.I.E.L.D.: 5.19: Option Two
- Agents of S.H.I.E.L.D.: 5.20: The One Who Will Save Us All
- Agents of S.H.I.E.L.D.: 5.21: The Force of Gravity
- Agents of S.H.I.E.L.D.: 5.22: The End
- Agents of S.H.I.E.L.D.: 5.08: The Last Day