'Chicago P.D.' season 4 spoilers: Platt and her father become victims of gruesome attack in episode 3; Jon Seda leaves series to join 'Chicago Justice'

Trudy Platt (Amy Morton) and her father will become victimized by a brutal assailant in the upcoming episode of NBC's cop drama "Chicago P.D." season 4.
Titled "All Cylinders Firing," next week's episode will see Platt find herself in a tough situation after being attacked by an unknown perpetrator. According to the official synopsis, Platt is out to visit her father Robert's (guest star Chelcie Ross) house for dinner and warns him to be cautious with his new girlfriend Natalie (guest star Lilia Vassileva).
After dinner, Platt heads to her car where she gets physically assaulted and rushed to Chicago Med. Her co-workers Voight (Jason Beghe), Lindsay (Sophia Bush) and Halstead (Jesse Lee Soffer) immediately go to the hospital to investigate, and a worried Mouch (guest star Christian Stolte) finds himself being interrogated by the cops.
Meanwhile, Antonio (Jon Seda) leads the Intelligence team at the crime scene as they find evidence and discover more about previous threats against Platt. However, his attention shifts when he gets a call to go to Robert's townhouse where he finds signs of an even worse attack on Platt's father.
On other related news, "Chicago P.D." star Jon Seda will be leaving the series to join another Dick Wolf-produced franchise, "Chicago Justice." According to reports, the actor—who has appeared in the cop drama since it debuted in 2014—is headed to NBC's upcoming spinoff for a series regular role.
Before "Chicago P.D.," Seda has portrayed the character of Detective Antonio Dawson during the early days of "Chicago Fire." On "Chicago Justice"—which premieres midseason 2017— Dawson will work as an investigator for the DA's office. He will be partnered with Lori Nagle, played by actress Joelle Carter from "Justified."
It's not yet known exactly when Seda will transition from Chicago P.D., which is currently in its fourth season.
The fourth season of "Chicago P.D." airs every Wednesday night at 10 p.m. EST on NBC.