'Chicago Fire' season 5 episode 9 air date, spoilers: Severide gets arrested for homicide; series to cross over with 'Chicago P.D.'

Dawson (Monica Raymund) and Casey (Jesse Spencer) finally meet Louie's biological father in the upcoming episode of NBC's firehouse drama "Chicago Fire" season 5.

Titled "Some Make It, Some Don't," the next episode will explore a huge problem in Dawson and Casey's family life. According to the official synopsis, Dawson and Casey are determined to sort out legal matters in hopes of staying as Louie's legal guardians. However, the arrival of Louie's biological father stirs up a new complication.

Severide (Taylor Kinney) continues to help Anna (guest star Charlotte Sullivan) with her bone marrow procedure, but things won't go as planned. He later finds himself slipping back into his old habits when an issue with the medical procedure arises. Meanwhile, Brett (Kara Killmer) opens up to Dawson about something that's bothering her, while members of Firehouse 51 suddenly become competitive — much to Chief Boden's (Eamonn Walker) dismay.

In the promo clip for episode 9, Severide wakes up with a gash on his on his forehead as he tries to remember what happened to him. "Chicago P.D." characters Lindsay (Sophia Bush) and Voight (Jason Beghe) appear in the next scene and knock on his door to let him know about the situation. "A mother and daughter were hit by your Mustang," Lindsay calmly tells Severide inside an interrogation room, but the firehouse responder claims that he didn't do it. However, the mother who was hit by Severide's car identifies him as the driver.

While the interrogation is ongoing, Voight enters the room to deliver some bad news. "The little girl in the back seat, she just died from her injuries," he said. "This just went from hit-and-run to vehicular homicide." At the end of the clip, Severide is seen in handcuffs as he rides a police vehicle.

The fifth season of "Chicago Fire" returns to the small screen on Tuesday, Jan. 3, at 10 p.m. ET on NBC.