It’s red kryptonite time on episode 16, “Falling,” of TV’s Supergirl. Not to be confused with its far more well known cousin, green kryptonite (the krpytonite that saps Superman and his fellow Kryptonians of their superhuman strength, in effect making them mere mortals, however temporarily), red kryptonite has an entirely different effect on the affected Kryptonian. It might turn a Kryptonian into a thief of high-end electronics, compel him (or her) to wear a leather jacket, and even ride a motorcycle with a helmet or a regard for speed limits. In short, red kryptonite can bring out a Kryptonian’s inner (family friendly/PG-rated) bad boy or bad girl. In Supergirl’s (Melissa Benoist) case, it brings out the worst in her, making her not only her own worst enemy, but the enemy of National City too. Under the influence of red kryptonite, she’s bitter, resentful, and petulant, eager to throw off her benevolent, unselfish, world-saving persona for an unfiltered, self-indulgent, egotistical one.
It’s not Supergirl’s fault, of course, but as episode 16 clarifies before the end credits roll, everything Supergirl thinks, says, and does are part of her, the return of the Kryptonian repressed so to speak, suggesting Maxwell “Don’ Call Me Mini-Lex Luthor” Lord (Peter Facinelli), may have been on to something with his instinctive distrust of and xenophobia against super-powered aliens. After all, Supergirl isn’t the only super-powered alien on Earth. Besides her far more famous, perpetually absent cousin, Superman/Kal-El/Clark Kent, there’s an entire crashed prison ship full of Kryptonians and other super-aliens quietly running amuck on Earth, including Supergirl’s recently deceased aunt, Astra (Laura Benanti), and Astra’s like-minded Kryptonian allies, including Non (Chris Vance), Astra’s husband and successor to Kryptonian leader.
Non and his vanguard of Kryptonian superman, however, are nowhere to be found in this week’s episode. Presumably they’re still off planning whatever they’re planning, presumably a little world domination with Kryptonians at the top of the (non) natural order. If Non gets his way, Supergirl will be dead, but a temporary truce, the result of a little known two-week mourning ritual, effectively acts as a truce. With the clock winding down on the temporary truce, Supergirl takes comfort in rescue missions orchestrated by Hank Henshaw/Martian Manhunter (David Harewood), the head of the Department of Extra-Normal Operations, and Alex Danver (Chyler Leigh), Supergirl/Kara’s adopted sister. A seemingly simple mission goes unpredictably sideways when Supergirl becomes exposed to red kryptonite, here artificial kryptonite created by none other than Lord himself.
Before Hank, Alex, Winn (Jeremy Jordan), and James Olsen (Mehcad Brooks) discover the cause of Supergirl’s odd, aggressive behavior, Supergirl/Kara manages to damage every professional and personal relationship. She trades her traditional superhero costume, for a form-fitting one-piece costume with a small, barely detectable “S” insignia and no cape, comes on too hard to the recently single Olsen (suddenly aggressive women are not his thing, apparently), tears into Alex for wanting to control her (a fair point, given the older/younger sister dynamic and Alex’s over-protective nature), and worse from a superhero point of view, not only confronts Cat Grant (Calista Flockhart), but drops her from her CatGo World Media’s office 40 stories up, all the while giving vent to a serious messianic complex and her desire to be worshiped and treated like a god. With Superman nowhere to be found, the task of taking down Supergirl and restoring her rightful place as National City’s primary defender falls on the DEO and Hank Henshaw.
When the battle begins to turn against the DEO and more importantly, Alex (she’s at Supergirl’s literal mercy), Henshaw finally drops the facade and comes out as the Martian Manhunter. Henshaw’s decision turns the tide against Supergirl (apparently, he can only activate his superpowers in his true, non-human form), but it comes at a personal price: His immediate arrest and detention. After all, the DEO was created specifically to deal with alien threats, not be led by alien in human guise with an unknown agenda. Episode 16 leaves Henshaw in an underground DEO cell, his fate and future uncertain. Not really, of course, given that he’ll be needed for the final fight against the slowly gathering Kryptonian menace. The episode also leaves Kara and Olsen’s romantic relationship in a precarious position. Olsen didn’t care for Kara/Supergirl’s dark side-inspired theatrics, not to mention (but we’ll mention it, anyway, for completion’s sake), Supergirl’s superhuman abilities, specifically her super-strength (she almost hurts him twice). In the meantime (i.e., next episode, aptly titled “Manhunter”), Kara/Supergirl has been left with the unenviable task of rebuilding the trust of her friends, family, and the citizens of National City.