Tonight's season finale of Supergirl was, like most finales, so preoccupied with telling its story and bringing a satisfying conclusion to the season that it didn't take much time for digressions like Easter eggs and references.
Nevertheless, there were a handful of things to be on the lookout for.
So...what did we see? What did we miss?
Read on, and comment below.
First of all, the idea of angels or guardian angels isn't one that's a stranger to Supergirl. As early as her first appearance, she was referred to in passing as a guardian angel, and it became a major theme during Peter David's run on the title in the '90s.
Second, we've seen multiple episodes called "Better Angels" in comic book shows. Before Supergirl, there were "Better Angels" episodes of Marvel's Agent Carter and The Walking Dead.
Rao, referenced several times this episode, is the Sun God of Krypton, and the planet's major deity.
In the very science fiction-heavy Silver and Bronze Ages of comics, Superman had a great many stories that revolved around Krypton, and Rao was therefore a major player. "Great Rao!" was something that Superman used to say a lot during that time, when he identified as a Kryptonian who had come to Earth.
Most more recent versions of Superman self-identify as a citizen of Earth, so we don't get the "Great Rao" much anymore, although recently Rao himself appeared in the pages of Bryan Hitch's JLA and did battle with Superamn and the Justice League.
"Stronger together," which is how Eliza Danvers describes their family when she's trying to talk Alex out of her mind-control, is a phrase that's come up periodically throughout the season.
It was a common refrain for Alura Zor-El, Kara's birth mother, and for her sister, the season's big bad Astra.
"Don't understand why they thought handcuffs would stop a MARTIAN," tweeted series star Melissa Benoist as J'Onn crumped his and discarded them.
Well, it might have been a wink and a nod to Man of Steel, in which Superman allowed himself to be handcuffed to make the human authorities feel more at ease, but then popped them off when it was "time to put all our cards on the table, General."
That necklace Supergirl was wearing seems to be a Command Key.
Like the necklace Superman wore in Man of Steel, it serves as a key to Kryptonian vessels. In Man of Steel, it was the Scout Ship, but in Supergirl it was her pod.
That's what Alex used to rescue Kara and get her back to Earth, and then she gave it back to her sister.