CW Synopses April 21-25

Here's the latest batch of episode descriptions from The CW.

Supergirl s4e18 "Crime and Punishment"

WILLIE GARSON GUEST STARS — Kara (Melissa Benoist) and Lena (Katie McGrath) head to Stryker’s Island to search for clues on how to defeat Lex. At the prison, Kara tries to befriend a nosy prisoner, Steve (guest star Willie Garson), who may have insight into what Lex was doing, while Lena studies an array of puzzles Lex left behind in the hopes of discovering his whereabouts. While there, a prison riot breaks out and Kara must find a way to stop the prisoners without revealing her secret identity as Supergirl. Meanwhile, Kelly (guest star Azie Tesfai) encourages James (Mehcad Brooks) to talk to someone for his PTSD, and Alex (Chyler Leigh) faces off against Ben Lockwood (Sam Witwer) after he storms the DEO and acquires some powerful weapons to hunt Supergirl. Antonio Negret directed the episode with story by Rob Wright and teleplay by Lindsay Sturman & Aadrita Mukerji (#418). Original airdate 4/21/2019.

Arrow s7e19 "Spartan"

ERNIE HUDSON (“GHOSTBUSTERS”) GUEST STARS — After the Ninth Circle delivers a major setback for Team Arrow, Diggle (David Ramsey) reluctantly reaches out to a Four-Star General of the Defense Intelligence Agency (guest star Ernie Hudson) for help, despite unresolved tension from their past. Meanwhile, Oliver (Stephen Amell) discovers a piece of information that he believes will turn Emiko (Sea Shimooka) against the Ninth Circle. Alena (guest star Kacey Rohl) returns with an interesting proposal for Felicity (Emily Bett Rickards). Avi Youabian directed the episode written by Benjamin Raab & Deric A. Hughes (#719). Original airdate 4/22/2019.

Legends of Tomorrow s4e12 "The Eggplant, the Witch, & the Wardrobe"

YOUR PERSONAL HELL — With darkness on the rise in 2019, the team realizes that a new host of problems have risen as they have been cleaning up history. Sara (Caity Lotz) tries to save Ava (Jes Macallan) from a fate worse than death while battling her own demons. Nora (Courtney Ford) and Constantine (Matt Ryan), work together to take down a powerful demon. Meanwhile, Zari (Tala Ashe) gets unsolicited advice from Mona (Ramona Young), Charlie (Maisie Richardson-Sellers) and even Rory (Dominic Purcell). Brandon Routh also stars. Mairzee Almas directed the episode written by Morgan Faust & Daphne Miles (#412). Original airdate 4/22/2019.

The Flash s5e19 "Snow Pack"

ICICLE RETURNS — When Icicle (guest star Kyle Secor) returns to enact the next phase of his devious plan, Caitlin (Danielle Panabaker) and her mother, Dr. Carla Tannhauser (guest star Susan Walters), must resolve their long-combative relationship to defeat the icy monster. After Barry (Grant Gustin) makes a big decision about their family without consulting her, Iris (Candice Patton) decides to take matters into her own hands. Jeff Cassidy directed the episode written by Jonathan Butler & Gabriel Garza (#519). Original airdate 4/23/2019.

Supernatural s14e20 "Moriah"

ALL HELL BREAKS LOOSE ON A SHOCKING SEASON FINALE – Sam (Jared Padalecki), Dean (Jensen Ackles) and Castiel (Misha Collins) are thrown into an epic battle. Meanwhile, Jack (Alexander Calvert) becomes disenchanted with all the lies, and an old friend from the past shows up. Phil Sgriccia directed the episode written by Andrew Dabb (#1420). Original airdate 4/25/2019.