When Lena found out that Kara and Supergirl are in fact the same person, she was pissed. Kara still didn't have enough guts to tell her by herself. Lena found out by encrypted message sent by her lovely brother from the prison.
Angry Lena is something you don't want to experience. She did not scream, no. She called clueless Kara to have a meeting where she told her that she doesn't want to see her again. Kara's pleading was useless. She was the only person whom Lena trusted and now it hurts like hell. To avoid such mistake again, she cut ties with all people known from Kara- Alex, Sam, James…
Long story short, it was a mess. So when Sara came that she needs help in another universe it was very welcome escape for Kara. Some shitty alien hid some weapon from this messy universe there and Kara's and Alex's help was needed. Nobody really cared for the details anyway (especially not Kara).
So now all three of them are walking streets of this unknown universe which looks quite similar as theirs.
"This is not parallel universe or future, it's both. For example this school", Sara pointed at the building in front of which they're standing, explaining, "can be in our universe in the future at the same place but can have only different color. We don't know"
"Okay, that's what we figured out. But why we have to be in this freaking disguise and you! don't?" not very happy Alex asked, maybe because now she is wearing wig with long hair, hat, sunglasses and summer dress with flowers- not very agent style.
"Because from what we know, the weapon- most possibly the bomb- is hidden somewhere close to you. Maybe in your or Kara's flat and we have to avoid the universal paradox. Which, I'm sure you know, happens when you look into your eyes directly. And because it fits you", Sara said with her typical wink. She knows that both of them are now happily engaged, she just couldn't help herself.
Alex wanted to respond but the focus of all of them was stolen by limousine which stopped few meters from them. And they knew why. The Luthor style is recognizable in every universe apparently. So they caught the magazines, very very smoothly (not), from the bookstall which was in front of school and watching the scene from behind the pages.
First who got off the car was no one else than Lena Luthor by herself. She looked magnificent. Even she was few years older she still looked beautiful, Kara thought. She was mostly silent. Maybe because she was kind of emotionally exhausted by that all mess she left at her world.
But surprise surprise! Lena was not the only one in the car. The second person getting off and now approaching her backpack is Lena's daughter. It was clear for everyone because she looked somehow like younger version of Lena. She could have 10-15 years, nobody from those 3 had kids, so that's how their guessing look like. Lena's daughter was so smiley, cute and full of life. She said her goodbyes to mum and headed to school. Lena was visibly on hurry so she left in the meantime.
That's when the girl stopped and turned around…
"Mommy?!"