One Chicago is ready to unveil its most ambitious crossover event to date. The franchise has treated fans to multiple crossovers over the years, but the 2025 event is guaranteed to be the best yet in the sense that every character and show will get the spotlight.
It will be a One Chicago Wednesday unlike any other, in terms of both storytelling and structure. There are going to be more than a few fans who tune in and are confused by the order of the three One Chicago shows: Chicago Med, Chicago Fire, and Chicago PD.
Chicago Fire is going to start the crossover event
While they typically air in the order in which they are listed above, the January 29 crossover will be a little different. Instead of opening with Chicago Med, NBC has decided to flip the order of the first two shows so that Chicago Fire kicks things off.
This makes sense, given that the event that initiates the three-part storyline is an emergency that the Firehouse 51 team is called to help clean up. It would make less sense structurally, to open with Med and the victims of said emergency being hospitalized.
This actually the same structure that the last One Chicago crossover assumed in 2019. Chicago Fire kicked off that storyline, which dealt with a deadly virus, before handing it off to Med. Chicago PD will hold down the fort in its usual time slot.
Chicago Med will occupy the second time slot
The correct order to watch the 2025 One Chicago crossover is Med, Fire, and PD. The episode titles will reflect this order, in that they will be called "In the Trenches: Part I," "In the Trenches: Part II" and "In the Trenches: Part III."
This also raises an important point for those who decide to catch it on Peacock the day after it airs, or simply enjoy the crossover so much you want to rewatch it. A binge of any of the One Chicago titles in isolation will not cut it. You cannot watch Med or Fire or PD in its isolated chronology because it will only give you one third of the crossover event.
It'll be very confusing to get the conclusion of the "In the Trenches" arc during a rewatch of Chicago PD season 12, but such are the risks of having a franchise come together for a singular event. It's the Avengers logic. We're frankly thrilled it's happening again.