It's Valentine's Day in National City.
Kara voiced her dismay at no longer working on cases with Alex, however, J'onn plays matchmaker and enlists Kara's help in solving a missing person investigation.
Turns out, his assignment ties directly into Alex's current DEO case.
Alex is trying to find a new kind of alien called a Menagerie that crashed on Earth and began eating people's hearts. Poetic, right?
With Brainy's help, they figure out that the snake-like alien is a symbiote that has connected with diamond-thief, Pamela.
When they ambushed Pamela in the home, Kara had to pretend to be herself so that she wouldn't blow her cover.
The snake only "bit" through her coat, but it was enough to cause Alex to worry.
She no longer wanted Kara to accompany them on any cases, which meant Kara couldn't work with her sister as herself or as Supergirl.
She later realized that maybe keeping Alex in denial about her secret identity is for the best as Alex will finally be able to worry less about her and focus more on her personal life, which includes adoption.
It seems Alex is finally ready to take the next step towards motherhood, especially after seeing how everyone around her -- Haley, Brainy and even J'onn -- had personal lives.
Though Colonel Haley wanted to keep the latest alien attack on the down-low, words got out and caused havoc in the streets.
The Children of Liberty rallied for Ben Lockwood's release so he could "protect them" from the aliens.
Lockwood enlisted his son, George, to put on the Agent of Liberty mask and rally the Children. George eventually killed the Menagerie telling the press he "did what Supergirl couldn't."
Nia ditched the Valentine's Day party her roommate threw her in order to help Supergirl fight the Menagerie.
After accepting her destiny as Dreamer, she asked Brainy, who has an obvious crush on her, to help her train and hone her powers.
Haley made it clear to Alex that she doesn't want Supergirl's help anymore.
She also approached Lena Luthor and offered her a government contract for her superhuman research.
While James thought it was a bad idea to allow the government to militarize her work to have an army that was "as strong as aliens," Lena disagreed and assumed he was "judging" her.
She broke things off shortly after inviting him on a romantic trip to Paris.
Around the same time she accepted the contract, the President decided that the best thing to do is free Ben Lockwood.
What's his plan?