- Not to be confused with the second season The Flash episode, Welcome to Earth-2.
- "Do the Hatfields mention the McCoys?"
- "I take it your two planets didn't get along?"
- —Kara and Alex Danvers
An attack is made on the President as hot-button, alien vs. human rights issues heat up in National City. Supergirl and the D.E.O. are assigned to protect the President and bring in the responsible party. Alex teams up with Detective Maggie Sawyer to investigate the case while Kara searches for a recently escaped Mon-El, who she fears may be the alien behind the assault.
- This is the first episode to not feature Cat Grant, following Calista Flockhart being downgraded to special guest star due the series relocation to Vancouver.
- Kara mentioned that Kryptonians and Daxamites were like the Hatfields and the McCoys. The two families had a rural rivalry that spanned from the late 1700's to the 1800's. No one truly agree how the rivalry started just as no one can agree on how the warring between the two planets started.
- A veiled reference is made to Diana Prince/Wonder Woman's Invisible Plane when President Olivia Marsdin tells Supergirl "you ought to see my other jet". Lynda Carter, who portrays the President, also portrayed Wonder Woman in the live-action series of the same name.
- Another reference is made to Diana Prince's spin transformation from the Wonder Woman TV series: when Supergirl notices she's on fire, she does a similar spin to put out the flames.
|Supergirl season 2|
|"The Adventures of Supergirl" • "The Last Children of Krypton" • "Welcome to Earth" • "Survivors" • "Crossfire" • "Changing" • "The Darkest Place" • "Medusa" • "Supergirl Lives" • "We Can Be Heroes" • "The Martian Chronicles" • "Luthors" • "Mr. & Mrs. Mxyzptlk" • "Homecoming" • "Exodus" • "Star-Crossed" • "Distant Sun" • "Ace Reporter" • "Alex" • "City of Lost Children" • "Resist" • "Nevertheless, She Persisted"|