'Supergirl' Returns, 'Riverdale' Goes Musical, 'Black Lightning' Ends & More: The CW April 16-20

Supergirl: Schott Through the Heart

OSCAR-NOMINATED ACTRESS LAURIE METCALF GUEST STARS

When Winn's (Jeremy Jordan) father dies, his estranged mother, Mary (guest star Laurie Metcalf), reappears trying to reconnect and to explain why she abandoned him all those years ago. Winn is too embittered from his rough childhood to forgive her but when a copycat Toyman attacks, the two must work together to stop him.

Mon-El (Chris Wood) tells Kara (Melissa Benoist) something important about the Worldkillers, and Alex (Chyler Leigh) becomes suspicious of Myr'nn's (guest star Carl Lumbly) recent behavior.

Glen Winter directed the episode written by Caitlin Parrish & Derek Simon.

iZombie: Don’t Hate the Player, Hate the Brain

IN DA CLUB

After consuming the brain of a bachelor playboy, Liv (Rose McIver) heads to a club to meet up with Clive (Malcolm) and Ravi (Rahul Kohli). Meanwhile, Major (Robert Buckley) is assigned an enormous task.

Lastly, Clive (Malcolm Goodwin) is still struggling with the arrangement he's made with Bozzio (guest star Jessica Harmon).

David Anders, Aly Michalka and Robert Knepper also star. Tuan Quoc Le directed the episode written by Sara Saedi.

The Flash: Lose Yourself

RALPH CONSIDERS CROSSING A LINE TO DEFEAT THE THINKER

When Barry (Grant Gustin) and Team Flash find a way to enter The Thinker's lair, Ralph (guest star Hartley Sawyer) considers crossing a dangerous line to defeat DeVoe.

Meanwhile, Joe (Jesse L. Martin) is concerned by Harry's (Tom Cavanagh) recent behavior.

Hanelle Culpepper directed the episode written by Jonathan Butler & Gabriel Garza.

Black Lightning

The season 1 finale for Black Lightning, which airs on April 17, will be titled "Shadow of Death: The Book of War."

Riverdale: Chapter Thirty: A Night To Remember

RIVERDALE HIGH PRESENTS "CARRIE THE MUSICAL"

As Riverdale High begins rehearsals for its upcoming production of "Carrie the Musical," the arrival of an ominous letter forces director Kevin (Casey Cott) to make a difficult decision about the show. Jughead (Cole Sprouse) uses his cover as the musical's documentarian to solve the mystery behind the letter.

Meanwhile, tensions between Betty (Lili Reinhart) and Veronica (Camila Mendes) continue to escalate just as Alice (Madchen Amick) announces she is joining the musical to spend more time with Betty.

Elsewhere, Hiram (Mark Consuelos) enacts a devious plan to further drive a wedge between Fred (Luke Perry) and Archie (KJ Apa), while Cheryl (Madelaine Petsch) channels Carrie White during a showdown with her mother.

Marisol Nichols, Ashleigh Murray and Skeet Ulrich also star. Jason Stone directed the episode written by Arabella Anderson & Tessa Leigh Williams.

Arrow: The Dragon

DIAZ SETS HIS SIGHTS ON THE QUADRANT

Looking to expand his empire, Diaz (guest star Kirk Acevedo) and Laurel (Katie Cassidy) meet with The Quadrant, a coalition of mafia families who run national organized crime. Meanwhile, after Oliver's (Stephen Amell) recent decision, Felicity (Emily Bett Rickards) and Curtis (Echo Kellum) double their efforts on building Helix Dynamics.

Gordon Verheul directed the episode written by Spiro Skentzos & Elizabeth Kim.