|Season 3, Episode 11 (51)|
|Brave New World||Siblings|
ALEX AND MAGGIE REACH AN IMPASSE- Shortly after returning to National City, Maggie spends the day searching for the "perfect ring" for Alex. In the present, Lena asks Eliza to accompany her to a fundraiser. On New Krypton, Kal challenges Zod's authority, and Alura gives Kara an ultimatum: embrace her Kryptonian heritage or be banished to Earth.
- Melissa Benoist as Kara Danvers/Supergirl/Kara Schott
- Chyler Leigh as Alex Danvers
- Jeremy Jordan as Winn Schott (Earth-6), Winn Schott, & Winn-X
- Katie McGrath as Lena Luthor & Lena-X
- Laura Benanti as Alura Zor-El & Astra In-Ze
- Tyler Hoechlin as Kal-El
- Zachary Quinto as General Dru-Zod
- Odette Annable as Samantha Arias/Reign
- Jenna Dewan as Lucy Lane
- Dianna Agron as Major Raya Zod-El
- Emmy Rossum as Zaora Dru-Zod
- Wallis Day as Junior Magistrate Nyssa-Vex
- with Claire Holt as Karen Starr/Power Girl
- and David Harewood as J'onn J'onzz
Special Guest StarsEdit
- Chris Wood as M'On-El
- Floriana Lima as Maggie Danvers (flashbacks)
- with Mehcad Brooks as James Olsen
- and Helen Slater as Eliza Danvers
- Brenda Strong as Lillian Luthor
- Harry Lennix as Commander Fer-Gor
- Tracy Spiridakos as Lesla-Lar
- Amy Jackson as Imra Ardeen
- Georgina Campbell as Lieutenant Asha Del-Nar
- Jesse Rath as Brainiac 5
- Chad Lowe as Thomas Coville
- Andrea Brooks as Eve Teschmacher
- Emma Tremblay as Ruby Arias
- Robert Gant as Zor-El (flashbacks)
- Anjali Jay as Indra Nim Gosa (flashbacks)
- Alessandra Torresani as Young Jindah Kol Rozz (flashbacks)
- Antagonist: None
- First appearance of Brainiac 5.
- This episode is Maggie-centric.
- The flashbacks in this episode help fill in several gaps between the 3-year time-jump.
- This episode is concurrent with Brave New World.