In this week's episode 'Wake Up', Mon-El (Chris Wood) is finally back. Since Supergirl season 3 began, Kara Danvers (Melissa Benoist) has been in mourning since she sent Mon-E away in order to save the Earth from a Daxamite invasion to conclude season 2. Thus far, the show has taken on a more somber tone that reflects our heroine's sadness. Fans and Kara herself hoped that Mon-El's eventual return would brighten up Supergirl back to her cheerful self. Instead, Mon-El's reappearance brings with him a whole legion of questions, only some of which 'Wake Up' shockingly answered.
The discovery of Mon-El ties into the space ship buried beneath National City, which was unearthed in a missile attack in the season 3 premiere. We had speculated that this ship was how Samantha Arias (Odette Annable), who just discovered she's the Kryptonian Worldkiller Reign in 'Wake Up', came to Earth and that the ship's cryogenic sleeper pods housed the other Worldkillers from Supergirl comics, but that turns out not to be the case. Instead, when Supergirl and the DEO investigated the mysterious ship, they found Mon-El inside speaking a new language - Saturnian.
Back at the DEO, Mon-El is maddeningly silent about where he's been. He's the same person Kara last saw seven months ago, but he's also somehow different (beyond him sporting a beard). Somehow he can now breathe on Earth despite the atmosphere still laced with traces of lead. Mon-El is definitely keeping secrets, and when he suddenly springs out of his hospital bed to attack some DEO agents and steal a device recovered from his ship, Supergirl is forced to lay Mon-El out. Soon, Mon-El finds himself in a detention cell, coming full circle to last season when he first landed on Earth and was held in a DEO detention cell to be interrogated by Supergirl. Despite her clearly being confused and emotionally distraught, Mon-El still refuses to explain himself to Kara.
Winn (Jeremy Jordan) does manage to get through to Mon-El enough to agree to let him out of the cell and accompany him back to the ship. Supergirl discovers the prison break and follows them, where some answers at last are revealed to what happened to Mon-El:
For Kara, it's been seven months since Mon-El rocketed away, but for him seven years have passed. While out in space, Mon-El's ship was pulled into a wormhole that sent him forward in time - to the 31st century. He returned to Earth and was cured of his weakness to lead poisoning because 400 years from now L-Corp develops a cure. What's more, his ship is from Saturn (yes, there's life on Saturn) and this helps explain Mon-El's fluency. The ship was also buried in the bedrock underneath what would become National City for 12,000 years (echoing the Kryptonian ship hidden under the arctic ice for millennia in Man of Steel).
There are other people from the 31st century in cryo-sleep on Mon-El's ship, and the life support begins to fail in one of the pods. Thanks to Supergirl having the strength to punch through white dwarf glass, they are able to save the pod's inhabitant - a woman named Imra Ardeen (Amy Jackson) - and bring her back to the DEO. Imra is from Saturn's moon Titan and she is Mon-El's wife! Though Mon-El continues to wear Kara's necklace as a reminder of their relationship and what she means to him, in the seven years he lived in the 31st century, Mon-El had to move on, thinking he'd never see Kara again.
In DC Comics lore, Imra is a telepath known as Saturn Girl and is one of the core members of the Legion of Superheroes. The Legion does exist in the Arrowverse continuity, as we have already sighted a Legion flight ring on The Flash and Supergirl. The reveal of Mon-El's time travels and of Imra herself confirms that the Legion will be part of Supergirl this season.
The Legion are already no strangers to The CW; in season 8 of Smallville, the Legion met Clark Kent (Tom Welling) when Cosmic Boy (Ryan Kennedy), Lightning Lad (Calum Worthy) and Saturn Girl (Alexz Johnson) arrived in Clark's hometown. With the mention of Chloe Sullivan as the childhood friend of Superman (Tyler Hoechlin) in last week's episode, popular aspects of Smallville are becoming canon on Supergirl as well.
While unexpected, the return of Mon-El and his forced silence was maddening for both Kara and fans until the answers finally came. However, Mon-El not knowing how to break the news to Kara that he's now married is understandable. With the immediate mystery of how Mon-El is back in 2017 solved, new questions begin to emerge: How did they travel back in time? Who else is in the cryopods? Presumably they are other members of the Legion, but if so, which?
Supergirl will be attending Barry Allen's wedding to Iris West and deal with her evil Nazi doppelganger in next week's Crisis On Earth-X crossover, so it may be a while longer before fans get the answers to all the questions we have about the Legion of Superheroes.
Are you pleased with Mon-El's return? Which other members of the Legion do you hope to see on Supergirl? Let us know in the comments.
Supergirl airs Mondays @ 8pm ET on The CW.