As part of their second phase of training, the rookies are asked to develop their first confidential informants. Officer Nolan soon discovers that no two informants are the same and struggles with his newest task. Meanwhile, Officer Chen’s mother complicates her home life when she comes to stay with her.

Nolan takes his son’s fiancé, Abigail, on a ride-along after she shows interest in becoming a police officer. Meanwhile, Jackson’s relationship is becoming complicated at work.

When professor Fiona Ryan’s car window is smashed following a series of mysterious notes, Nolan volunteers to guard her house overnight. Lucy notices that Tim is being much nicer to his new boot than he was with her and she does not like it.

After rushing his son, Henry, to the hospital following his collapse, Nolan is reunited with his ex-wife, Sarah, and they must come together to help their son. Meanwhile, Detective Lopez discovers “La Fiera” is in the same hospital and wants to find out exactly why.