'Chicago Fire' Wraps up Eventful Season Finale With Deadly Cliffhanger

Chicago Fire wrapped up its latest season with an exciting new relationship, and a cold case investigation leading to shocking cliffhanger.

Spoilers ahead for Chicago Fire Season 7 Episode 22: "I'm Not Leaving You"

The eventful finale episode started with a literal bang when the firehouse is surprised after an 8-year-old crashes a car as he desperately tried to take his mother to safety as she gave birth to a child in the backseat.

After helping the family with the safe delivery of the new baby, the episode circles back on Severide (Taylor Kinney) as he continues to work on the arsonist cold case his father was working on before his death.

Casey (Jesse Spencer) tries to make the first move with Brett (Kara Kilmer) after Boden (Eamonn Walker) invites him to an event where he has to bring a date. The conversation is interrupted when the other members of the team use Brett to practice their new sensitivity training.

Severide and Stella (Miranda Rae Mayo) work together looking at evidence of former cases, after a car fire seems to indicate the woman behind the repeated attacks is closer than they think.

He then gets a call with findings from the fire revealing a homeless woman was killed in the car fire, and him believing Carol must have lured the woman into the car and killed her.

The firefighters head to Carol's husband's home, and he says he doesn't believe she will be coming back. Stella tells him she knows what it's like to be in a taxi relationship and begs him to contact them if she returns. The speech overwhelms the man and he admits Carol is at the home. Stella gets hurt in the confrontation, but the pair manage to stop her from escaping.

After Carol is arrested, Severide and Stella are commended for their efforts. That night, Miranda celebrates at the bar and wonders where Severide is as the chaplain Kyle (Teddy Sears) finds Brett and tells him he is moving away for a new job.

Brett admits she is not happy to say goodbye to him, but wishes him well. When he walks away, Brett attempts to go after him but she runs into Casey, who says he is happy for her relationship with the chaplain.

After Casey says Severide acted strange before disappearing, Stella leaves the bar and finds him in his father's cabin. When she arrives, Stella tells him he is going to work on himself to be worth of her love and the pair share a passionate night, officially getting back together.

Before the star of shift the next day, the chaplain returns and confesses his love for Brett and asks her to marry him — and move away — as the team watches. The paramedic says yes, leaving everyone in shock. As the team celebrates, Casey congratulates Brett on the big news.

The fun is interrupted when the firehouse gets a call of a massive factory fire. The team works to save trapped workers from the dangerous blaze, when Severide notices a bunch of people trapped in a locked room.

As the team works, Casey realizes the basement will collapse before they can everybody out. Boden orders everyone to evacuate but Severide, Cruz (Joe Minoso), Herman and other firefighters attempt to help Severide and prevent the explosion.

The episode pulse-pounding cliffhanger when the basement is about to blow, and nearly half of the firehouse is in danger of being caught in the fire.

How will we make it through the long summer? Chicago Fire is set to return with new episodes in fall 2019 on NBC.