The state of Firehouse 51 is looking bleak on "Chicago Fire."

On the latest episode, "You Will Hurt Him," Dawson (Monica Raymund) and Casey (Jesse Spencer) are back together, and can't keep their hands off each other.

Dawson then goes to the station to find yet another temporary replacement for Shay (Lauren German).

Shay is still smarting after the robbery, and is becoming increasingly depressed. Severide (Taylor Kinney) pleads with her to rejoin 51, but she refuses. Later, Shay leaves a voicemail on Devon's phone, pleading with her to return all her stolen belongings. Then instead of going to her shift, she goes downtown to the bridge over the Chicago River.

Meanwhile, Leon (Jeff Lima) is undercover with the Insane Kings gang. Cruz (Joe Minoso) stops by to tell him about his wedding to Zoya, but Detective Olinsky tells him that no contact is allowed when Leon's undercover.

Leon eventually gets Doc to admit to first-degree murder, then a rival gang shows up and opens fire. CPD pulls out the bloody victims from the car, and finds that Leon is somehow unscathed. Cruz is then told that Leon needs to get out of the city to keep him safe, and it could be permanent. Cruz's initial anger turns to sadness, and he hugs his brother goodbye.

Severide then learns that Katie (Brittany Curran) is his sister, and that she's graduating from cooking school but her mom can't attend the graduation. Severide surprises Katie by showing up at the graduation and throwing her a surprise party at Molly's.

At the end of the episode, Dawson finds Shay on the bridge. Dawson is upset to see Shay in such a despondent state, and apologizes. Shay finally agrees to return to 51.

Yet, the gang is then greeted by McLeod (Michelle Forbes). She's written up a liability charge for the firehouse, and says Firehouse 51 will be shutting its doors for good.

On the next "Chicago Fire," the firefighters of 51 refuse to go down without a fight.

In "Not Like This," "All seems lost with firehouse 51 on the verge of closing its doors, thanks in no small part to Gail McLeod (guest star Michelle Forbes), but Chief Boden (Eamonn Walker) and the rest of the house refuse to allow themselves to sit by and let it happen. An emergency call to an apartment structure fire tests everyone's limits and puts the squad in harm's way. Meanwhile, Dawson (Monica Raymund) receives some life-changing news and union president Greg Sullivan (guest star Eric Slater) makes headlines, which has an immediate impact on Mouch (Christian Stolte)."

Watch the promo for "Not Like This," which airs Tuesday, Dec. 10 at 10 p.m. EST on NBC.