[2] The Intelligence unit races against the clock as more people get infected by the deadly flesh-eating bacteria sending the city of Chicago in a panic.

Later on, the Intelligence unit discovers that the killer is wanted by the FBI in six states for creating a sex trafficking ring.

The Intelligence unit continues to investigate a series of fatal overdoses of counterfeit oxy on young teenagers including former Chicago patrol officer Sean Roman's (special guest star Brian Geraghty) sister Sarah.

Intelligence does everything they can to build a case against the elusive leader of a drug ring, but things get complicated when Rojas realizes someone she cares about might be involved.

Actor Jon Seda, who plays Antonio Dawson, departed the series at the end of the sixth season due to creative reasons.