A Chicago Fire timeline of Matt Casey and Sylvie Brett's romance

Matt Casey (Jesse Spencer) and Sylvie Brett (Kara Killmer) have not had the smoothest path to happiness, but what would the fun in a smooth path be? The drama that these two have incurred over the course of their time on Chicago Fire is part of why we root for them, and part of what made their sudden reunion in the season 11 finale so rewarding.

Well, seeming reunion. We won't know if they got engaged until the season 12 premiere, but given that Brett is gearing up the leave the show, we'd say the odds of her saying yes are high. Casey and Brett go way back, as longtime viewers can confirm, so we thought it'd be useful to assemble their highlights as a couple ahead of their triumphant send-off.

Casey and Brett meet in S3 E1 ("Always")

It's important to begin at the beginning. Casey and Brett met under pretty bleak circumstances in season 3, considering that the latter was coming in to replace the deceased paramedic Leslie Shay (Lauren German). They didn't interact too much, but it's interesting to see them in the same setting, interacting with Gabriela Dawson (Monica Raymund) more than each other.

Related: 4 ways Brett could be written off Chicago Fire

Dawson would, of course, go on to marry Casey and become friends with Brett, so it may be a little jarring for fans who haven't gone back to watch the early seasons for a long time. Still, any Brettsey list has to start here.

Brett gets engaged in S7 E22 ("I'm Not Leaving You")

Casey and Brett had some flirtatious moments throughout the middle seasons of the show, but it all came to a screeching halt in the season 7 finale, when Kyle Sheffield (Teddy Sears) proposed to Brett at the firehouse. She said yes, and even left Chicago for a brief time, leading Casey and the viewers to believe that the window for the Brettsey romance was closed.

Casey and Brett had some tricky romantic games to get through in later seasons (remember when Brett dated Casey's nemesis, Greg Grainger, in season 9?), but the fact that she came to her senses and returned to Chicago, single, in season 8, proved that there will still unresolved feelings to deal with.

Casey and Brett finally kiss in S9 E2 ("That Kind of Heat')

Season 9 was important for Casey and Brett as a prospective couple. Casey suffered a head injury on the job, and Brett stood by him the entire time, then the favor was repaid when Casey stayed the night at Brett's after she had been held up at gunpoint. It all culminated in the episode "That Kind of Heat", when they shared they first kiss.

Related: Chicago Fire boss teases Brettsey proposal drama in S12

Season 9, of course, marked the official start of their relationship. It seemed as though nothing was going to stop them fro a happily ever after, but then the Darden family resurfaced in Casey's life, and he decided to relocate to Oregon.

Brett breaks up with Casey in S11 E1 ("Hold on Tight")

The couple tried the long distance thing for most of season 10, but it proved to be a little too much for Brett, who broke things off in the season 11 premiere. She was pretty dejected by the way things had gone down between her and Casey, but she did eventually get out and date again. She had a brief romance with bartender Dylan (Christopher Allen), but nothing significant came out of it.

Casey returned to Chicago a few times during season 11, and while there were efforts made to seem like both him and Brett were over their romance, their behavior made it clear to everybody else they still had feelings for each other.

Casey proposes to Brett in S11 E18 ("Red Waterfall")

Casey decided to take the plunge and get down on one knee in the season 11 finale. He visited Brett at her apartment, reminded her that they shared their first kiss there, and then proceeded to ask her to marry him. It was a shocking moment for Brett and the fans, and of course, it cut to black before we could get an answer.

Related: Chicago Fire promo photos reveal Brettsey proposal outcome

Barring a major upset, which would be one of the biggest bait-and-switches in Chicago Fire history, Brett will say yes, and the two of them will be married. It makes the most sense, especially given that Brett is planning to leave Chicago as well (Casey is already living in Oregon). It's the perfect outcome for this drama-fueled romance!