New episodes of One Chicago air on Wednesdays on NBC, with Chicago Med at 8 pm ET, Chicago Fire at 9 pm ET, and Chicago PD at 10 pm ET.
During the 2025 three-hour event, Firehouse 51, Gaffney Chicago Medical Center, and the Intelligence Unit join forces to catch the perpetrators behind the gas explosion, treat the injured (like Trudy Platt), and rescue trapped civilians (a group that includes Stella Kidd and Adam Ruzek). The One Chicago crossover also features new tandems as many characters have yet to meet. Of course, some characters get more screen time than others. However, the overlap between all three series and their stories comes in full force as “In the Trenches” raises the stakes in the fictional universe.
10Kidd & Severide Are Reunited (& Planning A Trip)
Severide claims they should take their time and plan the vacation instead of rushing into it. Kidd counters that “more time” will never magically appear. So, they have to make the time happen (a sentiment that comes back around at the end of the crossover), but trip planning must wait as Severide and Kidd are late for work. Unfortunately, this morning scene between Severide and Kidd is their last peaceful moment of the three-hour One Chicago crossover.
Viewers don’t have to wait long for characters from different shows to cross paths in Chicago Fire‘s segment of the crossover. A few minutes into the hour, Violet Mikami reveals that Dr. John Frost is joining Ambulance 61 for a ride-along that day. Frost is new to the One Chicago universe, making “In the Trenches” his first crossover. Luckily for Chicago Med season 10’s new doctor, the event makes good use of his character.
At the beginning of “In the Trenches,” Firehouse 51 responds to a gas explosion at Chicago’s City Employee Benefits Department building. It’s unclear what caused the explosion at first. Nevertheless, Chief Pascal takes over the scene, commanding the other Chicago Fire season 13 characters to perform search and rescue and investigate why the explosion happened. Meanwhile, he appoints Violet to lead the triage efforts. However, the big concern is cutting off the gas. The gas company takes too long to arrive, though, and Chief Pascal, Sam Carver, and Darren Ritter take matters into their own hands to stop the leak.
Before Kidd (and Adam Ruzek) get stuck underground on the CTA train, Severide and Christopher Herrmann check out the source of the gas explosion in One Chicago‘s 2025 crossover. They discover that the building’s servers’ electrical distribution system was rigged to overheat, and find an open oxygen tank in a room that belongs to the employees’ pension fund. Consequently, as Severide explains, the place turned into a powder keg, causing the gas explosion.
A data storage drive containing the assets ($250 million) was kept in the targeted room to prevent hacking — they were worried after public outcry in response to the fund investing its money in cryptocurrency.
As for how Ruzek gets stuck alongside Kidd on the train, it all starts when Severide comes across two men trapped in the server room. He frees them, but one pulls a gun on the firefighter. The suspect begins shooting and doesn’t hit Severide, but the commotion alerts Ruzek, Trudy, and Bates (a security guard/former cop Trudy knows). They split up, with Trudy tracking one offender, and Ruzek chasing the other. The suspect leads Ruzek down to the subway tunnels and the stuck train, and the cop loses him but knows he’s hiding in plain sight among the trapped passengers.
Meanwhile, Trudy catches the other suspect. However, while she has her gun trained on him, an unknown third party creeps up behind Trudy and shoots her three times in the back. They both get away, and Mouch is the one to find Trudy. They rush her to the hospital, and based on Dr. Caitlin Lenox and Dr. Mitch Ripley’s assessment of Trudy’s condition, things don’t look good for her.
Throughout the rest of 2025’s tense One Chicago crossover, Trudy’s life hangs in the balance. However, just when it seems like the original Chicago PD character will die, Trudy pulls through. When she wakes up, Trudy is able to give Voight vital information that ultimately helps them solve the case.
As a chief, Herrmann must command the scene of a disaster. He must resist the urge to run into the fire alongside his fellow firefighters. However, Pascal is the chief during the One Chicago crossover. So, Herrmann explains to Pascal that he wouldn’t be able to live with himself if he didn’t join his team in the trenches (which is undoubtedly where the crossover gets its name) because the scene already has a chief. Pascal lets him go, but Herrmann’s eagerness gives him pause, possibly setting up future tension between the two characters.
Eamonn Walker joined the several other actors who exited Chicago Fire during season 12 when his character, Chief Boden, said goodbye in the finale
For the most part, Voight and Pascal are cordial. They never truly butt heads, if one doesn’t count Pascal stopping Voight from sending his officers to the source of the gas explosion to collect evidence. The two One Chicago characters ultimately work well together to investigate the crime and lead their respective teams. Hopefully, “In the Trenches” isn’t the last fans have seen of this duo.
It’s a great sign that Goodwin feels good enough to show up during the special three-hour event. Plus, she never looks as if she’s in pain or tired. As a result, Chicago Med fans should expect Goodwin to return to the medical drama very soon.
The Chicago Fire segment of the 2025 One Chicago crossover introduces Bates, the government building’s security guard and a former police officer who previously worked with Trudy and Voight. Bates is present throughout the three-hour event as she “helps” the first responders. However, Voight later discovers that Bates was one of the people behind the attack. She was also the one who shot Trudy, almost killing her. Bates explains that she was diagnosed with mesothelioma and needed her pension. As mentioned above, though, the city cheated people like Bates, making her lose the money.
Bates’ accomplices include Margaret, a worker at the City Employee Benefits Department who was also diagnosed with mesothelioma. She sued her place of employment, but the lawsuit was dismissed. Like Bates, Margaret was under the characters’ noses the entire time. She is the Jane Doe victim with severe burns and the mother of the young girl who Frost helps throughout the crossover. As for the perpetrator on the train, Duffy, a man who consistently helps Kidd and Ruzek, is the person Ruzek was chasing. He had a mask on at the time, so the Chicago PD character didn’t recognize him.
The big question looming over the One Chicago universe‘s 2025 crossover is whether Kidd, Ruzek, and the other trapped passengers will be saved before their oxygen runs out. Luckily for them, Intelligence gets their hands on the suspects’ subway schematics. With it, Pascal, Severide, Herrmann, Mouch, and Archer are able to breach the tunnel’s walls from the building next to it. Just when they arrive, though, Duffy grabs Kidd and points his gun at her head.
Kidd manages to get away from Duffy, and Ruzek attempts to take the gun from him. They struggle until the gun goes off, killing Duffy moments before the tunnel starts to collapse. The first responders guide everyone off the train and are able to save everyone (except for Duffy, of course). Ruzek grabs the pension fund’s drive from Duffy beforehand, though.
On the surface, Severide reunites with Kidd, who both commit to taking the time to go on their vacation as soon as possible, while Ruzek and Burgess also embrace. As Chicago Fire showrunner Andrea Newman told NBC Insider prior to the three-hour event’s premiere, the disaster tests the two couples’ relationships. Fortunately, they make it out on the other side and everyone survives the One Chicago crossover.
