After the tire slashing incident, Casey's had enough of Voight's antics. He shows up at the police station to give him a piece of his mind, publically reprimanding him for his actions and making it very clear that he's not afraid of Voight. He tells Voight that he's not going to drop the charges against his son, so it's best if Voight just stays away from him and Hallie.
The police show up at the fire station regarding Casey's public scene and attempt to strike a deal with Casey and Boden. The head of the precinct tells Boden that his hands are tied; he can't do anything about the harassment when he really has no clear evidence to go on. All Casey's asking for is a better alternative from getting down in the dirt and handling this incident on his own. The police chief concedes that off the record, he'd be happy to watch Voight go down himself. Dawson's brother volunteers to head the investigation into Voight and this harassment on the down low and help out Casey in any way he can.
The squad gets called in for a rescue mission, as two construction workers dangle on the side of a roof where their harnesses have come undone. Severide climbs down to help the men and gets thrown for a loop when all the pressure is put on his seriously injured arm. It's no mystery that this is the last straw for Severide, and he holds his arm in agony after completing the rescue.
It turns out Casey's visit to Detective Voight just fueled the fire, as two thugs pay him a visit and beat him to a pulp in an alley. The police do their best to track the thugs to Voight, but they still don't have enough to go on. Casey's frustration mounts, and Boden warns him not to act rashly; they're going to approach this the right way. Meanwhile, Hallie's concern grows as she constantly calls Casey to make sure that everything's okay.
Cut off of pain meds from Shay, Severide's left with no choice but to find a new way to manage the pain. He hits up an old flame who also happens to be a pharmaceutical rep, asking for a favor. She's more interested in rekindling their relationship, and Severide begrudgingly obliges if it means getting what he needs. Later, we see Severide popping the pills she illegally provided, just happy to get a moment of relief.
Dawson's still in deep with the ethics committee after her incident with the little girl from an earlier accident. Luckily, her actions actually saved the girl's life; so hopefully her case will be dropped, and she'll be able to continue her career as a paramedic. But when she kicks a drugged-out witness on a later call who tries to fight his way onto the ambulance, it looks like she may be in a whole new mess of trouble. The man in question decides to press charges, leaving Dawson in a compromising position.
Though Dawson continues to secretly pine over Casey, it seems that she's been able to make a connection with another person at the station: Peter Mills. Their friendship based on a love of cooking may be platonic, but there's definitely some serious flirtation there. Mills playfully harasses Dawson about the secret ingredient to her amazing mac and cheese recipe, until she agrees to cook the dish for him.
Voight's harassment knows no bounds, as he tracks down Hallie and pulls her over in his cop car. He asks her to do him a favor and talk some sense into Casey, noting that he'd hate to see things get uglier than they already are.
When Casey hears about Voight's bold move towards his fiancee, he finally reaches his breaking point and decides to take matters in his own hand. He stalks Voight at the station, watching him from his car with a crowbar in the passenger seat. But Boden's onto Casey and follows him there before he can do any damage. He takes the crowbar from Casey and insists that somehow, they'll find a way to fix this the right way. But when Casey leaves and Boden's standing with the crowbar in hand, we see a fire in his eyes that may imply otherwise.