For the most part, “Ace Reporter” plays out like a traditional monster-of-the-week episode of Supergirl, where the most curious aspect is the question of whether or not it was intentional for the one-off villain, Biomax, to be given a nano-bot gimmick reminiscent of the nemesis from Big Hero 6, given that his name already sounds so much like that same film’s friendly robot, Baymax. True to form, the whole thrust of the episode seemed to mainly play out as a way of resolving the story thread of Kara’s firing from CatCo - she’s back now. Oh, and chalk up one more “maybe/maybe not” exchange as to whether or not Lena Luthor has figured out Kara’s secret identity; since it was the heiress’ previously unmentioned ex-boyfriend who turned out to be the victim (and also perpetrator) of the Biomax threat - which you’d figure would be a bigger deal than it was played as.

But, as has been the case throughout Supergirl’s second season, that unexpected hierarchy of plotting (such as a big piece of Lena’s backstory being casually raised and dispatched as the B-story to Kara reconciling with gruff editor Snapper Carr) turned out to be about setting up the pins for the next game. With Lena now left in an emotionally vulnerable state, forced to end the life of her onetime lover in order to thwart the supervillain who’d turned him into a weaponized puppet (and worried that the only thing currently making her feel better was the thought of said villain suffering), she’s visited by a new would-be business partner with a vague proposition - a business partner viewers will immediately recognize as the evil Queen Rhea (Teri Hatcher.)

That Rhea is still hanging around Earth and (presumably) looking to cause trouble for Supergirl isn’t good news, but it’s also not particularly surprising. Her decision to stay in the neighborhood to exact vengeance on Kara for turning Mon-El against his parents (and killing her own husband to do so) made that clear enough, and everything else about her character has screamed “I will figure prominently in however this season ends” since she first appeared.

Having Rhea turn up just to (apparently) make Lena Luthor part of her as-yet-unrevealed machinations makes a lot of sense and should worry fans who’d like to see Lena’s character remain on the side of good - or even just make it out of Season 2 alive - to their core. Left in the latest of a series of shaken states, Lena is in the best possible position to be manipulated by Rhea stepping into a role the erstwhile Luthor most definitely doesn’t need but may find herself wanting: a new bad mother.

Like most of The CW’s DC offerings, Supergirl is fundamentally a show about relationships that happens to occupy the superhero genre. While those relationships come in several varieties, the series is (perhaps unsurprisingly) preoccupied with relationships between women, be they romantic (Alex and Maggie), friendly (Kara and Lena), or maternal. That last one is especially prominent. Kara spent much of Season 1 in conflict with older female relatives of her biological mother while also being “mothered” to one degree or another as an adult by her adoptive mom or by Cat Grant, while Lena’s more abstract arc of getting out from under her family’s bad name was made more direct when her (already unpleasant) mother, Lilian, turned out to be the leader of the anti-alien hate group, CADMUS.

When Lena betrayed her mother earlier in the season, it initially appeared as if she was serious about shedding her family’s bad habits, putting her firmly on the self-determination side of her nature versus nurture arc. But it’s easy to see how Rhea (another domineering, calculating maternal figure) slipping into that vacant mother role might make Lena more receptive to her influence now that she’s hurting once again - especially since she doesn’t know exactly who this new mystery associate actually is. Unfortunately, even an alliance based on deception would mean nothing but bad news for Kara, given that Rhea is still carrying around a spaceship full of kryptonite and kryptonite-based weaponry, meaning Lena, being Lex Luthor’s last blood relative, now has access to an already-established cache of anti-Superman/Supergirl weapons of her own (one of which, the iconic War Suit, has already been displayed once).

Sure, it feels like a given that the title character will survive whatever the forthcoming season finale throws at her; but the implication of a Rhea/Luthor team looks like bad news for the good guys. Rhea has already killed one family member out of spite, so Mon-El is also hardly guaranteed to escape unscathed. Depending on how far Lena gets pushed, she might make trouble (intentionally or not) for other alien semi-regulars via either her brother’s stockpiles or the leftover CADMUS gear - especially if finding out that she’s been deceived by one alien and manipulated by another pushes her into embracing her family’s traditional hatreds after all (remember, full meaning behind an earlier flashback to mastering chess-playing skills with Lex has yet to be fully explained).

One way or another, Supergirl has only a handful of episodes left before Season 2 concludes (in a 2-part season finale set to feature the return of Callista Flockhart as Cat Grant) - so fans won’t have to wait too long to find out.

Supergirl continues Monday, May 1 with ‘Alex’ at 8pm on The CW.