The CW official released a summary for October 23rd’s episode of Arrow.
“OFFICER LANCE’S PAST PUTS LAUREL IN DANGER — Lance (Paul Blackthorne) learns a criminal named Barton Mathis (guest star Michael Eklund), whom he put away years ago, broke out of prison during the quake and is back to torturing and murdering women. Felicity (Emily Bett Rickards) offers herself as bait so Arrow (Stephen Amell), Diggle (David Ramsey) and Lance can catch this villain, but the plan goes awry. Furious, Mathis kidnaps Laurel (Katie Cassidy) in retaliation and plans to murder her while Lance watches. Meanwhile, Thea (Willa Holland) and Oliver are stunned when District Attorney Adam Donner (guest star Dylan Bruce) seeks the death penalty for Moira (Susanna Thompson). Oliver asks Roy (Colton Haynes) to help him find the Canary (Caity Lotz). Glen Winter directed the episode written by Marc Guggenheim & Keto Shimizu (#203).”