Plot summary
Andy and Marlo have an out of control drug arrest, which leads to the discovery of a deadly bacteria in the drugs, which turns into a city wide outbreak, which Sam tries to control. The two ladies are stuck in a decontamination process and quarantine, when Marlo reveals a big secret about herself. Dov and Chloe's new romance is off to a rocky start when Dov thinks she's hiding something.
Credits
Adapted from Wikipedia contributors, Rookie Blue season 4. HTML formatting and reference markers removed.