Many suspects emerge after a rich tycoon's new, young wife is shot during a deer hunt; Kate and Megan's relationship takes a turn for the worse.

A pharmaceutical rep is found dead in the Schuykill River, but when Megan Hunt and the team investigate, there's no blood found in her body. The team must locate the original crime scene to see if they can find the cause of death, but with suspects who have access to hundreds of unknown drugs, they may never know who or what killed her.

When a recent lottery winner is found brutally murdered, everyone becomes a suspect.

Megan investigates the death of a bride on her wedding day; Ethan has a crush on the new girl, but she is interested in someone else.

When a woman suspected of murdering her son is found innocent, Megan and the team try to identify the real killer; an overzealous reporter makes the investigation difficult by sensationalizing the case.

The parents of a seemingly perfect family are murdered; Curtis grapples with his new position; Megan's romantic life heats up.

When a city-wide outbreak of a mysterious and lethal virus occurs, even Megan and her team are at risk. In order to determine who and what caused this outbreak, CDC Officer Charlie Stafford takes over the investigation.

Megan comes face-to-face with a convicted serial killer she helped put away.