Nevertheless, She Persisted

"Nevertheless, She Persisted" is the twenty-second and final episode of the second season of Supergirl, and the forty-second episode overall. It aired on May 22, 2017.

Synopsis
Supergirl challenges Rhea to battle to save National City. Meanwhile, Superman returns and Cat Grant offers Supergirl some sage advice.

Trivia

 * This is the last episode of Floriana Lima as a series regular as she is later downgraded to recurring for Series 3.
 * This is the last episode of Katie McGrath as a guest star prior to becoming a series regular with Season 3.
 * The title of the episode is a reference to a phrase used by U.S. Senate Majority Leader Mitch McConnell after silencing objecting Senator Elizabeth Warren during a nomination hearing on February 7, 2017. Sen. McConnell later gave an explanation: "She was warned. She was given an explanation. Nevertheless, she persisted". The phrase "nevertheless, she persisted" went viral, quickly becoming a trending hashtag and feminist rallying cry.
 * Cat makes another topical reference by uttering the term "fake news".
 * Cat Grant likens James Olsen to Darth Vader, beating up villains. Kara and Clark correct her mistake, telling her that he beat up the good guys. This is a reference to Guardian's voice-changing technology that makes his voice noticeably deeper, albeit warped. She also makes mention of villains slaying him with their "lifesaver", soon to be corrected for her mistake.
 * Cat also claims to have never even seen Star Wars, a tongue-in-cheek reference to the fact that her husband, Harrison Ford, portrayed a central character in the original trilogy.
 * Superman makes mention of Warworld, which in the DC comics was an artificial planet on which he was forced to fight in gladiatorial games.
 * Cat mentions having turned down two marriage proposals from Rob Lowe.
 * Cat tells Kara that she is on "a hero's journey", noting its use by mythologist and writer Joseph Campbell.
 * Rhea mentions Star City, revealing there is a Star City on Earth-38.
 * It is confirmed that Cat is aware that Kara is Supergirl.
 * The destruction of Krypton is confirmed as occurring 35 years prior to the present day.