When a deadly car accident leads Charlie and Rex to investigate reports of a mysterious blue light in the sky, they discover the truth is more science than fiction.

The horrors of war haunt Frankie when the investigation of a soldier’s murder reunites her with a friend left traumatized by his tour of duty.

Convinced that Sarah is The Executioners final target, Tom Winston escapes from prison. Also Sarah discovers that Dylan knew about her past prior to meeting her.

Sarah finds herself at the center of a series of copycat killings and visits the man who murdered her parents in prison and he imparts a cryptic message.

Mary confronts Ben. Grady blackmails Mary into helping him break a patient out of the hospital. Ben and Frank get a new lead.

Mary seriously considers giving up her operations for good.

When Dr. Mary Harris becomes romantically involved with an attractive patient, it sets off a chain of events that could destroy her life, her family, and her career – not…

Wynonna and Waverly have a Halloween they’ll never forget as Rotten Jack terrorizes Purgatory.

Eph and Nora finally see their lethal virus in action. Fet takes the security of Red Hook into his own hands while Dutch and Setrakian set off for Staten Island…

Eph and Nora experiment on their newfound patients. Fet and Dutch grow closer as they clear out the neighborhood buildings, and Kelly begins her hunt for Zack.

Dutch returns with a plan to broadcast Eph’s warning about the vampiric plague. However, they face a new threat when Eichhorst launches his own attack against the pawn shop. Palmer…

Setrakian, Eph, and Nora formulate a plan to track down the Master using Jim as bait. Eichhorst and Setrakian’s pasts are revealed. At the Luss home, Neeva struggles to protect…

Eph races to safeguard his family, only to learn that Kelly is missing. Dutch reveals her role in Palmer’s plan, and Gus is forced to make a difficult decision about…

With Nora gone, Eph reluctantly joins Setrakian’s quest in hopes of gathering enough evidence to warrant a citywide quarantine. Fet encounters the unexpected inside the subway tunnels, and a medical…

New information from the Lumen forces Setrakian to seek help from his lifelong nemesis, Eldritch Palmer. Eph’s new experiments to understand strigoi communication seemingly take him to the brink of…

Harvard ethics professor Henry Gerard seeks Harvey’s help with a case that requires a lack of ethics to win. Mike, meanwhile, does his best to not be spotted by the…