Supergirl Recap With Spoilers: Kara Takes a Wild Trip Down Memory Lane in "It's a Super Life"

Supergirl hit its milestone 100th episode on Sunday night with "It's a Super Life" and with the Girl of Steel still struggling with the way her friendship with Lena has collapsed, it's an opportunity for Kara Danvers to take a look back to see what might have been. Fortunately, Mxyzptlk shows up to offer her that opportunity, but will seeing the options play out lead Kara down a new path, changing reality as we know it or is there a bigger lesson to be learned? What things will Kara discover? Read on to find out.

Warning: full spoilers for Supergirl's 100th episode, "It's a Super Life" below.

The episode opens where last week picked off. Mxyzptlk shows up at Kara's door and she lets him in. Mxyzptlk explains his previous form was one he chose to impress her; this is his real face. He also can only use his powers to help those he wronged and Kara is the last one. He offers her a do-over with the Lena situation, to see what the world looks like if she controls the narrative for herself. Kara sends him away and J'onn shows up for dinner. Kara serious considers Mxyzptlk's offer and despite Alex and J'onn's concerns, she summons Mxyzptlk back.

After sending Alex and J'onn to their "happy place" and explaining the rules, Mxyzptlk and Kara begin. They revisit the past, ending up in Season 4 in Lena's office before Mercy Graves attacks. Kara goes into that moment and reveals herself to Lena. Despite a heartfelt approach, Lena leaves and goes to tell Sam. Lena hasn't taken the news well, concerned that Kara really believes her to be a villain. The fallout from that is, despite Lena wanting to save Kara from the Kryptonite-poisoned atmosphere (courtesy Agent Liberty), she can't make it back from Metropolis to save her. Kara dies.

They go back a bit further, to the conversation when Kara first confronted Lena about Kryptonite. Kara reveals her identity to Lena again and, again, Lena doesn't take it well. She still feels betrayed and Lena decides not to help the DEO. This time, Mon-El doesn't go to the future so she goes to speak with him for his perspective. He gives her a pep talk about it all and gives her some hope. Lena shows up to save Sam, but Reign still survives and kills first Lena, then Mon-El before also dying.

They go back even further, closer to the beginning of their friendship. She drops in and reveals herself to Lena well before they are truly genuinely friends. Kara places her trust in Lena and they become partners. They apparently start to do a lot of good in the world, leading to a trial of Lillian Luther in which Lena refuses to reveal Kara's identity. However, in this timeline, Ben Lockwood's father opens a Cult of Rao church resulting in his whole family killing themselves because they believed Supergirl would save them. Lena is kidnapped by Lockwood. Supergirl has to reveal herself or Lena dies. Winn gives Supergirl a pep talk and it convinces Kara to reveal her identity at a press conference. She saves Lena, but it results in all of her friends -- and Cat Grant -- being murdered by Agent Liberty.

Realizing that there is never a good time to tell Lena, she decides to see a world in which she and Lena were never friends at all. That world seems pretty bleak and Kara decides that she just wants to leave, but Mxyzptlk's powers suddenly do not work. They're stuck. In this world, Lena rules. Kara and Mxyzptlk are saved by Dreamer and taken to the Tower. Lena is a dictator in this world with Supergirl declared a terrorist. It turns out that when Lena first came to National City, Lex's assassination attempt left her injured and she came back a monster. Lena is also using fifth dimensional powers to power her tech. Winn has an idea of how to get Mxyzptlk some powers via Hat, but Reign and Evil Brainy show up. A fight ensues. Supergirl goes to Lena.

Lena confronts Supergirl for not being there when it mattered and hits her with a blast of Kryptonite. Things are going terribly for the good guys overall, but J'onn eliminates Reign, Dreamer subdues Brainy. Lena is about to kill Supergirl but Mxyzptlk gets the hat and gets them out of there in time. Back at home in the real world, Kara realizes that she has to live with the mistakes she's made in reality. There is no perfect time to fix things. Mxyzptlk helped her. She releases him and tells him she's proud of him and how he's changed. Mxyzptlk leaves, but one tape is left behind - a reality in which Lena chose to work with Lex, the current one. Supergirl goes and tells Lena that if she decides to forgive her, she'll help her, but if she chooses to work with Lex she will treat her like any other villain.

At home, Kara has a special moment with Alex and J'onn, grateful for them being with her from the very beginning.