The Bottle Episode

Synopsis
The subsequent complications from the Crisis leave Supergirl to face a chaotic threat.

Starring

 * Melissa Benoist as Kara Danvers/Supergirl
 * Chyler Leigh as Alex Danvers
 * Katie McGrath as Lena Luthor
 * Jesse Rath as Querl Dox/Brainiac 5
 * Nicole Maines as Nia Nal/Dreamer
 * Azie Tesfai as Kelly Olsen
 * Andrea Brooks (credit only)
 * Julie Gonzalo as Andrea Rojas
 * Staz Nair as William Dey
 * David Harewood as J'onn J'onzz

Special Guest Starring

 * Jon Cryer as Lex Luthor
 * Cara Buono
 * Meaghan Rath as Brainiac 5

Guest Starring

 * Brenda Strong
 * Anjali Jay
 * Rosemary Hochschild
 * Winsome Brown

Co-Starring

 * Keith Dallas as Al/Al #2

Trivia

 * The episode shares the exact same title as the webisode from the DC Super Hero Girls webseries, given that both episodes featured Supergirl. In addition, this is the second episode to feature Supergirl and DC Super Hero Girls episodes sharing the same episode names. The first was which in-turn was adapted from the Superman arc For the Man Who Has Everything.
 * A "bottle episode" refers to one that typically takes place in a limited number of locations, often simply a single room. These episodes will use minimal budget, while usually restricting the cast to only series regulars.
 * For Supergirl, the title references the bottle containing Kandor.