“They walk the thin blue line where justice isn’t black and white—it’s personal.”

Chicago PD is a vastly different show in Season 12 than it was at the beginning — and not just because it’s been 12 seasons. The NBC series looked and felt different when it premiered in 2014, with a cast that still had several fan-favorites and was more well-rounded. It also existed in a time before the increased scrutiny surrounding law enforcement and how police officers are depicted on TV, painting Hank Voight and the rest of the Intelligence Unit in a more forgiving light.

One thing that hasn’t changed is how important Chicago PD Season 1 is to the One Chicago brand. The premiere of Chicago PD is what made One Chicago a franchise, and the success of the spinoff paved the way for there to be two more shows after it and for Dick Wolf to grow beyond the Law & Order brand. Without audiences falling in love with Voight and his team, the TV landscape as a whole wouldn’t look the same either. The first season does great things, and has some bittersweet moments, but it’s unquestionably the beginning of something special.

Chicago PD Season 1 Has a Much Stronger Cast

Some Characters Are Still Sorely Missed

The Chicago PD Season 1 cast is what makes the show a hit, and in retrospect, seeing their strength is a reminder of what’s missing from the more recent seasons. It’s easy to forget that Wolf Entertainment was developing a Chicago Fire spinoff almost from the jump; both the characters of Hank Voight and Antonio Dawson were introduced in Fire‘s third episode. What’s interesting is the ability of the creatives to turn Voight from an antagonist for Jesse Spencer’s fan-favorite Matthew Casey to the hero of his own show. The Voight initially introduced on Fire is markedly different from the one in PD; Wolf and creator Matt Olmstead didn’t just drag and drop. They also shook up their cast between the backdoor pilot and the “official” first episode — and the end result was much better.

The original cast included actors Kelly Elam, Scott Eastwood, Tania Raymonde and former Law & Order: SVU ADA Melissa Sagemiller. The latter’s character was infamously killed off in the Season 1 premiere, while the others were recast — which is how CPD got Jesse Lee Soffer, Sophia Bush, Patrick John Flueger and Marina Squerciati. It’s mind-blowing to think that none of those four were part of the original ensemble given how much they’ve all contributed to the series. Of those four, Flueger and Squerciati make the biggest leaps forward in Season 1. Prior to being cast as Adam Ruzek, Flueger’s biggest role was playing Shawn Farrell in USA’s sci-fi drama The 4400… a much more idealistic and naive character than Ruzek has ever been. Squerciati immediately brings a lightness and energy that Chicago PD needs as it wades into dark corners that Chicago Fire may not venture to, and the chemistry between her and LaRoyce Hawkins is some of the best in all of One Chicago, period.

But the core of CPD is the trinity that exists between Voight, his best friend Alvin Olinsky and Antonio Dawson. That trio is the foundation of the show and what it stands for. Voight has already been established as the hard-charging cop who will stop at nothing, but both Olinsky and Antonio bring different perspectives to contrast him and give the series additional depth. Sometimes Voight is right, sometimes Antonio is, or sometimes nobody is, but within those three characters the show has a broad range of perspectives. After the murder of Olinsky and sending Antonio off to rehab, Chicago PD is now almost entirely through one person’s lens: Hank Voight. And when sometimes even Voight doesn’t know what he’s thinking, that has made the show much less nuanced than it used to be.