Jon Cryer makes an uncredited appearance as Lex Luthor. The scene he appears in is a deleted scene originally meant as a flashback in The House of L (2019).
In DC comics, the Medallion of Acrata is an ancient Mayan symbol which represented the shadows in the night; as such, Andrea was able to teleport once she entered a shadow. "Acrata" is also Andrea's code-name in the comics.
The nickname Andrea's father, Bernado, calls her ("mi cielito") means "my little sky" in Spanish.
Most of the episode is flashbacks to Andrea and Lena's lives, going from boarding school to the present day.
There are a large number of flashbacks including: when Lena Luthor decided to move to National City after Supergirl stopped the Myriad attack in Better Angels (2016), when Supergirl and Superman saved Lena Luthor in The Adventures of Supergirl (2016), Lex Luthor telling Lena that Kara Danvers is Supergirl in The Quest for Peace (2019), Lena Luthor watching Supergirl save a school bus on the news in Event Horizon (2019). This episode also includes a flashback with-in a flashback from O Brother, Where Art Thou? (2019). In a flashback, Kara Danvers was shown to wear the exact same blue top as she wears in Girl of Steel (2017) and Damage (2017). Lena Luthor was shown to wear her yellow and white dress from Parasite Lost (2018). Kara wore her striped sweater from Will the Real Miss Tessmacher Please Stand Up? (2019).