Infection Part 2. An entire apartment complex is forced into quarantine when cases of the deadly virus turns into an epidemic.
The entire Boston Police Department searches for Alice Sands; the team investigates a suspicious car crash; a new romance blossoms.
Infection Part 3. PD chases a lead that could point to a case of bioterrorism and Will gets dangerously close to the suspect.
Brother's Keeper. A murder in a Bulgarian neighborhood results in a challenging investigation when locals won't talk to police. Ruzek has a clash with a patrol officer.
Familia. After a botched carjacking turns out to be something much bigger, Voight's unit goes toe to toe with a smart drug kingpin who only works with women.