One of the more epic crossover events in "One Chicago" history was a 2019 multi-episode spectacular, "Infection, Parts I, II and III." Immersing viewers in a three-hour marathon of high-intensity drama, it tells the story of a city facing a terrifying and lethal mystery illness.
It's "Chicago Med" that kicks off the action as a deadly bacterial epidemic sweeps across Chicago. With the assistance of the CDC, the Firehouse 51 squad races to identify the source and control the situation, with a frightening lack of success. In the second hour, "Chicago Med" team members risk their own health to treat a citizenry increasingly panic-stricken by what appears to be a highly infectious flesh-eating bacteria.
In the crossover's concluding chapter, the detectives of "Chicago P.D." take over to organize the biggest manhunt in department history in a race to stop the bioterrorist behind the disease outbreak. After successfully resolving the crisis, all three teams are gathered together as Dr. Sharon Goodwin (S. Epatha Merkerson) addresses them, saying, "Fear is a funny thing ... it brings out the worst in people. But fear also brings out our very best ... And for a certain few, fear brings out something different, their choice to be heroic ... to find a way to hold onto hope and to lean on each other like family."
The truth is, her remarks sum up not only this trio of episodes, but also the overarching credo for all three series, spotlighting this moving scene as absolutely among the very best "One Chicago" franchise crossover moments of all-time.
