With his nightclub set to open and a new romance brewing with McKenna, Oliver is as happy as he’s been since returning to Starling City. But when Oliver’s ex, The Huntress, suddenly returns to town, she threatens to destroy everything and everyone he cares about. Meanwhile, Laurel and her father struggle with the return of Dinah Lance who claims she has proof Sara is still alive. Thea gets Roy Harper a job at Oliver’s club, but he’s not too inclined to stop his life of crime. Oliver and Tommy are thrilled they were able to get Steve Aoki to play at the opening of their new nightclub, Verdant.

With tensions still running high between Chief Boden and Bennie Severide, things boil over when Mills confronts Bennie about the fire that killed his father. Meanwhile, Severide, Casey and Bennie uncover the truth behind two mysterious diner fires and Shay takes a new direction with her plan to have a baby.

The BAU investigates victims who were documenting their personal lives and inner desires on blog posts and social media. Also, Kevin gets jealous when he learns Garcia may have a new love interest.

At his wife's urging, David reluctantly attends his high school reunion -- which becomes a crime scene when the bitchy former high school queen is found dead in a back room.

Actress Eva Mendes; a Top Ten List presented by IndyCar driver Graham Rahal; comic Andy Hendrickson; musical guests The Airborne Toxic Event.

A woman claims that Brian Cassidy raped her while he was working under cover; when Cassidy and his lawyer utilize surprising defense methods, Detective Amaro is affected.

Castiel reappears in Sam and Dean’s life and tells them Crowley has unleashed several demons into a small town. The demons are looking for Lucifer’s Crypt, which holds a valuable asset, but Castiel lies to Sam and Dean about what it is. While interrogating a demon, the three discover Crowley has been torturing Meg, who knows the exact location of the crypt. Sam and Meg fight to hold Crowley off while Dean and Castiel go in search of the crypt.

Philip and Elizabeth must stop an assassin from taking out key US scientists, while Stan and the FBI hunt the same man. Grannie shocks Elizabeth with the truth of what happened between Philip and Irina in New York.

From "Olympus Has Fallen", actor Aaron Eckhart; musician Kellie Pickler.

In the Season 3 finale, Blake worries about the future and the supremacy of machines when Alice unveils an automated phone system at the office.