A priest seeks out Lucifer's help when he suspects an underground drug operation has set up shop at a neighborhood youth center. Meanwhile, Malcolm manipulates a way to keep an eye on Dan.

Guilty and self-destructive, Lucifer clashes with Chloe during an investigation, leading her to team up with Dan instead. Meanwhile, Amenadiel bonds with Charlotte, and Maze takes Trixie trick-or-treating.

Lucifer must find the antidote to the Professor's poison before it kills Chloe. He travels to hell to find the Professor's soul and get him to turn over the antidote. While he's there, he is forced to confront his guilt about Uriel's death. Mom heads to hell to get Lucifer back, but Lucifer still feels betrayed by his parents because of something he discovers.

When a food chemist is found dead, Lucifer and Chloe's investigation pits them against an unexpected face - criminal defense attorney Charlotte Richards. Everyone is caught off guard when they see her back in the precinct. As Lucifer tries to understand her return, he makes a shocking discovery that helps solve the case.

A reporter seeks revenge when he discovers Lucifer has been sleeping with his estranged wife; a serial killer from Lucifer's past resurfaces.

When a jewelry designer is murdered, Lucifer and Chloe strive to solve the case without each other's help. Also, Lucifer reconnects with an old flame.

Chloe learns a serial killer may have embellished his crimes. Amenadiel worries about his son's health. Pete opens up to Ella.

Lucifer angles to be his father's successor. Ella makes a painful confession. Chloe investigates a murder at an aquarium.

Lucifer tries to enjoy what may be his last day on Earth, Dan's killer escapes from prison, and Chloe drops a serious bombshell.