Each One Chicago show features a different aspect of first-responder work, with Chicago Fire being about members of the Chicago Fire Department’s Firehouse 51, Chicago P.D. focusing mainly on the Intelligence Unit’s attempt to keep the streets safe, and Chicago Med offering medical-based storylines at the Gaffney Medical Center. While there is much debate about which One Chicago show is the best, many fan-favorite episodes are crossovers in which characters from the different shows work together to solve a problem that affects everyone.
14. Chicago Fire Season 7, Episode 15 (“What I Saw”) / Chicago P.D. Season 6, Episode 15 (“Good Men”)
Cruz Goes Undercover To Help Voight Catch Robbers
That said, Cruz’s relationship with Chicago PD characters has always helped connect the two shows, so in that sense, it was important that he be the one to go undercover rather than a random person who was never seen again. However, this crossover still loses points because it would have worked just as well as a standalone episode that includes Cruz visiting Chicago PD without the Chicago Fire installment.
13. Chicago Fire Season 1, Episode 23 (“Let Her Go”): Chicago P.D.’s Backdoor Pilot
There Would Be No Spinoff Without This Episode

Technically, “Let Her Go” is not a crossover, as Chicago PD didn’t exist yet. However, it was a backdoor pilot for the spinoff, which means that the characters from Chicago PD appeared in an episode of Chicago Fire to introduce them to the audience and establish the relationship between the spinoff and the parent show. This episode was a far better backdoor pilot than many, as the connection between the new show and the old one was more than coincidental.
The main plot of this pilot episode establishes the relationship between the Intelligence Unit and Firehouse 51, with Casey working with Voight to find out who set the fire and killed Hallie. This is an emotional story for Casey which also gives the audience insight into who Voight and his team are as they all work together. Thus, while it wasn’t as exciting as some other crossovers, “Let Her Go” offers a solid introductory story for the Chicago PD cast.
12. Chicago Fire Season 3, Episode 19 (“I Am the Apocalypse”): Chicago Med’s Backdoor Pilot
This Backdoor Pilot Was More Memorable Than PD’s
The gas leak story would have been strong enough on its own. Still, the episode also included a violent hostage taker who screams, “I am the Apocalypse” and exposes the entire staff to a deadly pathogen. This theme would be repeated in another crossover later, “Infection.” This intense scenario set the tone for the new series while also working perfectly as a standalone episode of Chicago Fire. However, Chicago PD should have also been involved, considering there was a hostage situation that needed to be dealt with and Jay’s brother was one of the doctors trapped inside the hospital.
11. Chicago Fire Season 3, Episode 13 (“Three Bells”) / Chicago P.D. Season 2, Episode 13 (“A Little Devil Complex”)
An Intense Episode That Might Have Confused Casual Viewers
While it was easy enough for a casual viewer to follow the plot, this crossover didn’t work as well for them as self-contained stories that require no previous knowledge of both shows.
While some people watch every One Chicago show, others might only watch one and tune into the others when there’s a crossover that stretches over all three episodes. Usually, crossover episodes are self-contained, but in this case, the story was the resolution to something that had previously happened during Chicago Fire. Thus, those viewers who didn’t watch Fire regularly might not have cared about Shay or understood the significance of this story. While it was easy enough for a casual viewer to follow the plot, this crossover didn’t work as well for them as self-contained stories that require no previous knowledge of both shows.
10. Law & Order: SVU Season 15, Episode 15 (“Comic Perversion”) / Chicago P.D. Season 1, Episode 6 (“Conventions”)
The First Time One Chicago Connected With Dick Wolf’s Other Franchise
While this is a strong episode, it has been rightly criticized for not having a strong connection between the Law & Order: SVU and Chicago PD halves. Instead, Law & Order: SVU resolves its case, which involved a stand-up comic accused of sexual assault, by the end of the hour, only for Erin Lindsey (Sophia Bush) to enter Benson’s office and tell her that the Intelligence Unit needed her help to find a serial killer. Thus, this is more like a standalone episode where Benson works with Voight and Lindsey than a true crossover.
9. Chicago Fire Season 3, Episode 21 (“We Called Her Jellybean”) / Chicago P.D. Season 2, Episode 20 (“The Number of Rats”) / Law & Order: SVU Season 16, Episode 20 (“Daydream Believer”)
A Much More Tightly Connected Crossover Than The First Time
This three-part saga was a far better crossover; it involved all three teams and didn’t rely on a random connection at the end of the first part. Instead, this story revolved around a joint investigation that involved Law & Order; SVU as well as both the police and fire departments in Chicago The connections were all logical, enhancing the strength of the crossover, and it also involved the cold case trope, which often makes cases more interesting.
The only flaw in this story was that it didn’t involve Chicago Med. However, this crossover occurred only two episodes after Chicago Med‘s backdoor pilot, so the writers might have felt it was too soon to include the newest addition to the lineup. Additionally, since this story already involved three different shows, it might have stretched the plot too thin to include Med. Still, the medical drama’s absence was felt, especially when investigating a rape connected to an apartment fire.
8. Chicago Fire Season 5, Episode 9 (“Some Make It, Some Don’t”) / Chicago P.D. Season 4, Episode 9 (“Don’t Bury This Case”)
Severide Is In A Precarious Situation Throughout This Crossover
Severide is put through the wringer in this crossover. He spends most of Chicago Fire season 5, episode 9 trying to find a bone marrow donor for Anna, only to end up in serious trouble after his car is involved in a deadly crash. This allows the story to shift into Chicago PD‘s piece of the two-part story, which begins with the cops questioning Severide about the incident. The idea that a carjacker stole and crashed his car is a bit far-fetched, but the police’s questions add to the stress Severide feels throughout the hour.
7. Chicago Fire Season 3, Episode 7 (“Nobody Touches Anything”) / Law & Order: SVU Season 16, Episode 7 (“Chicago Crossover”) /Chicago P.D. Season 2, Episode 7 (“They’ll Have to Go Through Me”
The Second SVU Crossover Is Full Of Dramatic Tension
“Chicago Crossover” and its associated shows are easily the best of the three Law & Order: SVU crossovers. Although Chicago Fire was mostly a standalone episode, the tie-in was far more clear than the one in “Comic Perversion,” as it involved an actual case, and it was intensely personal for Lindsey. Law & Order: SVU is pulled into the story when Severide finds a box of pornographic images of children at a fire scene, and the plot thickens when one of those photos is of Lindsey’s brother, Teddy. However, the episodes shine because of the tension between Voight and Benson.
Benson and Voight are similar in that they’re both committed to justice. However, Benson is firmly by the book, at least to the extent that she does not approve of vigilantism or bending the law so far it almost breaks in an attempt to gain information or make arrests. Thus, she doesn’t take well to Voight’s rogue cowboy approach. However, romantic sparks fly because of the way the two butt heads, which is interesting because Benson compares Voight to Stabler.
6. Chicago Fire Season 4, Episode 10 (“The Beating Heart” / Chicago Med Season 1, Episode 5 (“Malignant”) / Chicago P.D. Season 3, Episode 10 (“Now I’m God”)
The First Crossover To Feature All Three One Chicago Shows
What starts out as an ordinary episode of Chicago Fire is soon revealed to be anything but.
These episodes are especially interesting because of the twists and turns they take. What starts out as an ordinary episode of Chicago Fire is soon revealed to be anything but, as a team member’s life-threatening injuries soon morph into a medical mystery surrounding a fire in a building and a scheme to send people for overdoses of chemotherapy being linked to Voight.
5. Chicago P.D. Season 5, Episode 16 (“Profiles”) / Chicago Fire Season 6, Episode 13 (“Hiding Not Seeking”)
A High-Stakes Story Begins In Chicago PD And Ends In Chicago Fire
The crossover that begins in “Profiles” reverses the usual trend by having the Chicago PD part of the series air first instead of last. This is one of the most tense stories in One Chicago history, with Voight racing to find a bomber who has targeted media personalities. Contacting Firehouse 51 is a logical step for Voight because the firehouse employs experts, some of whom know how to dismantle it. bombs or figure out where they came from. The partnership between the two departments is a welcome reprieve from people getting in each other’s faces over who’s the better team.
However, although the two departments get along, Boden isn’t happy with the idea of Voight recruiting an undercover operative from his ranks — again. This conflict raises the stakes significantly and is relatable.
4. Chicago Fire Season 2, Episode 20 (“A Dark Day”) / Chicago P.D. Season 1, Episode 12 (“8:30 PM”)
Another Bombing Story That Is Even More Intense
While “A Dark Day” also revolves around FIrehouse 51 and the Intelligence Unit joining forces to stop a bomber, it is completely different than “Profiles.” This episode is one of the most intense of any One Chicago series. A bomb has already exploded, causing mass carnage in Chicago, and the teams are racing against the clock to find the bomber before they can strike again. This story is both heart-pounding and heart-wrenching, as Burgess’ niece fights for her life during the chaos.
3. Chicago Fire Season 7, Episode 2 (“Going to War”) / Chicago Med Season 4, Episode 2 (“When to Let Go”) / Chicago P.D. Season 6, Episode 2 (“Endings”)
The Halstead Brothers Fear They May Lose Their Dad
2. Chicago Fire Season 8, Episode 4 (“Infection: Part I”) / Chicago Med Season 5, Episode 4 (Infection: Part II”) / Chicago P.D. Season 7, Episode 4 (“Infection: Part III”)
This Strong Story Unfortunately Became Reality Soon Afterward
“Infection” was a strong three-part story about a deadly virus that was spreading through the city while the doctors struggled to identify and contain it. Unfortunately, the episodes aired only a few months before the COVID pandemic hit, ironically making the final One Chicago crossover event in five years one that dealt with a similar disease. Each episode played one beat of this devastating story perfectly. Chicago PD season 7, episode 4 is especially memorable because it revolves around trying to catch the bioterrorist who unleashed the deadly bacteria before they strike again.
1. Law & Order: SVU Season 17, Episode 14 (“Nationwide Manhunt”) / Chicago P.D. Season 3, Episode 14 (“The Song of Gregory William Yates”)
Chicago PD Lost A Team Member In One Of The Scariest Episodes
Nadia’s death is so devastating that it is memorable years after it first aired, which is what makes this the best One Chicago crossover thus far. It will be difficult for any crossover episode, including the one set to air on January 29, 2025, to match the level of emotion as Benson and Voight’s teams join forces in the hopes of finding Nadia alive, only to discover that Yates killed her before they could catch up with him.











