'Supergirl': Kara's Connection to the Legion of Super-Heroes Revealed in "Reign"

Kara Danvers got a heartbreaking surprise a couple weeks ago on Supergirl when Mon-El returned only to reveal that he was married. Tonight, another surprise rubbed a little more salt in that wound.

Spoilers ahead for "Reign," the midseason finale for Supergirl's third season!

On tonight's episode of Supergirl, Mon-El (Chris Wood) and Imra Ardeen (Amy Jackson) explain to Kara (Melissa Benoist,) Alex (Chyler Leigh,) J'onn (David Harewood,) and Winn (Jeremy Jordan) how they ended up in a space ship in the National City waterfront. It turns out that the 31st century isn't a great place, so when Mon-El arrived, they brought various heroes together to help world leaders keep the peace and deal with threats, terrestrial and in space. That group? The Legion of Super-Heroes. But then they shocked Kara by explaining that she was the inspiration for the group.

It turns out that Mon-El started the group because he was inspired by Kara, so the group formed itself off of Kara's work as Supergirl. Imra in particular tells Kara that not only did Kara's example inspire the creation of the group, but it completely changed Imra's life, helping her find a purpose. Kind of makes it difficult to dislike your previously-believed-dead boyfriend's wife from the future when she idolizes you.

The origin Mon-El and Imra give Kara for the Legion is very similar to the group’s origin in comics. Prior to the Zero Hour reboot in 1994, the origin of the Legion of Super-Heroes centered around Superboy. Lightning Boy, Saturn Girl, and Cosmic Boy were so inspired by Superboy that they created a "super-hero" club and named it the Legion of Super-Heroes. However, the comic book version of the Legion took the extra step to travel back in time to recruit Superboy into their ranks, while on Supergirl, Mon-El and Imra end up coming face-to-face with Supergirl in much the same way that Mon-El ended up in the future in the first place. He explains that a wormhole like what he passed through that took him to the future ended up sending the whole team 12,000 years into the past. Realizing they couldn't get home, they put themselves into cryosleep with a timer set to wake them up when they returned to the 31st century.

Obviously, that didn't go quite to plan. Damage to their ship led them wake up in the present, and while Kara is clearly trying to live up the inspiration Mon-El painted her out to be, it's a heartbreaking situation for the heroine. And it's not going to get any better. Reign is awake and wreaking havoc on National City.

Supergirl airs Mondays at 8/7c on The CW.