In the final episode before the show goes on hiatus until April, Supergirl goes up against the second Worldkiller as Mon-El works to change the battery on the Legion time ship.

Previously, on SUPERGIRL

After discovering the identity of one of the two other Worldkillers destined to assist Reign in decimating the planet last episode, Supergirl leads the DEO into her home and find… a normal woman sitting on the floor of her house singing “Stay” by Lisa Loeb. She turned the radio on, she turned the radio up and this woman was singing her song. Too bad Supergirl and a bunch of soldiers with guns scared the crap out of her. The woman, Julia Freeman, panics as she begs to not be shot until, eventually, her Worldkiller persona, Purity, takes over.

While Kara and Alex debate the best methods to interrogate Purity, who is having none of it and is just looking to mess with the sisters until she has the best time to use her sonic powers to escape. All of this Worldkiller activity notifies Reign – who as Samantha was with her daughter ice skating after Lena forced her to take a day off – and she catches up with everyone during a chaotic battle underneath the subway. When all looks lost, Alex, who was serving as bad cop earlier, appeals to the Julia side of Purity and banishes the dark side, only for Julia to offer herself up to Reign. The pair go off to the Fortress of Sanctuary as Reign plans to find the third Worldkiller, Pestilence.

We also get some needless drama between Mon-El and Imra, because Mon-El apparently isn’t over Kara, and holding that back from Imra is causing some stress. The couple were a political marriage to unify future civilizations, though they were friends before the wedding. Mon-El says they grew to love each other, though he never had closure with Kara. J’onn gets Mon-El to be honest with Imra, who admits to being less than honest with him. Turns out she plotted a dangerous secret mission with Brainiac 5 – though viewers have no idea what it is yet. I’m guessing it has something to do with saving Supergirl, though…

Meanwhile, Samantha finally confides in Lena that she’s having more trouble than she’s willing to admit. Lena, who watched after Ruby when Reign took over and left her at the ice skating rink, says she knows what’s wrong with Reign and she’s going to help. Again, what Lena “knows” is left vague and something to pick up on in a later episode…

This episode set up a lot going forward, and plot development is always appreciated. But with the show going on a break until April for LEGENDS OF TOMORROW to run the rest of its season starting next week, this episode felt like it should have been bigger. All three Worldkillers uniting, the rest of the Legion of Superheroes showing up. SOMETHING to leave us wanting more. But we’ll get to all of that on April 16, when the show returns for its final run of episodes.