TELEVISION EPISODE REVIEW: Supergirl S3 Ep17 (Trinity)

With the three Worldkillers united, Supergirl and the DEO team scramble to stop them once and for all.

Supergirl – “Trinity”, Season 3, Episode 17
Airdate: May 7, 2018
Writers: Caitlin Parrish and Derek Simon / Story: Jessica Queller
Production Company: Berlanti Productions / Warner Bros. Television

What You Should Know:

Supergirl and the DEO team discover that Lena Luthor has been secretly holding her assistant Samantha Arias in an isolated L-Corp medical bay. Just when they ask her why, the Worldkillers, Purity and Pestilence, appear and unite with Sam. They then see that Sam has transformed into the Worldkiller Reign. With the three united, they become supremely powerful. They fly away from L-Corp to congregate their powers, leaving  Supergirl and the DEO team in a state of shock.

What You’ll Find Out (Spoilers):

Lena Luthor apologizes to the DEO team for keeping Samantha Arias’ dual identity a secret. She explains that Sam is close to her, and when she discovered Sam’s secret, she felt compelled to do whatever she could to help her friend before the Reign persona completely took over. When J’onn tells her that she should’ve come clean with the DEO in the first place, Lena reminds him that she is not an employee of the DEO and that the DEO in itself is a government shadow organization. She reiterates that she did do everything by the book, under L-Corp process. Supergirl then tells her that she still kept secrets, and that as friends, Lena should’ve told her everything. Lena then makes a very direct point in stating that, even though they’re friends, Supergirl still keeps secrets from her too. Lena then challenges Supergirl that if they want to put all secrets out on the table that she should share with her what her true name is. Supergirl is taken aback, and submits that she can’t do that. Lena tells her, fine, that they must all agree that there are secrets among all of them and that everyone must come to terms with that fact.

Back at the dark desert fortress, the three Worldkillers are greeted by the fortress AI program. The digital Kryptonian priestess explains that now that they’re together, their powers are augmented to the point that they can create changes on a planetary scale. The Worldkillers then practice their new abilities by causing an instantaneous solar eclipse. The effect causes not only world darkness but also causes Supergirl to feel weakened at the slow drainage of her powers.


The DEO is at a loss for how there could be a solar eclipse, as there is no scientific cause for how it could physically happen so quickly. Supergirl surmises that the eclipse is probably caused by the Worldkillers and that they are using a form of Kryptonian magic to do it. She explains that in her world’s religion, that there are mentions of witches who could bring about darkness. She feels that the Worldkillers could represent these witches. In a moment of weakness, Supergirl passes out and finds herself on the same alternate plane of existence Sam experienced previously once Reign took over her body. Supergirl is briefly able to decipher that both Sam and Purity’s human host Julia Freeman are on the plane too before she comes to back at the DEO headquarters.

When she explains what she experienced, Lena shares that Sam experienced the same other world visits too while under her care. Supergirl explains that she recognizes the other world as a part of Kryptonian lore. She surmises that she must return to the plane so that she can try to reach Sam and Julia to make sure that they are okay, and to try to strengthen their resolve to take ownership of their bodies back.

Supergirl remembers how Brainiac 5 was able to mentally reach her before once she was trapped within her own mind, using the future technology on-board the Legion team’s spaceship. She asks Brainiac 5 if he can repeat the process, but with roles reversed. Intrigued, he starts on the modifications necessary to make it work. Just then, both Alex and Lena tell Supergirl that they’re going with her too. Although Supergirl initially objects, the two women manage to convince her that there is strength in numbers.

Before they attempt the mind travel, Supergirl goes to James Olsen and asks for a favor. She informs him of what Lena has done, and reveals that she was able to keep Reign in check by exposing her to Kryptonite. While Lena explained to Supergirl that the Kryptonite was left over from Lex Luthor’s era and that the Kryptonite reserves are now depleted, Supergirl is still not sure. She asks James to sneak into L-Corp as his alter ego Guardian to find out that the Kryptonite is definitely no more. He’s very hesitant but does it. He manages to make it to Lena’s secured vault, but just when he is about to open its doors, he has a change of heart and leaves it closed. He then lies to the DEO, telling them that there is no more Kryptonite.

Once Brainiac 5 makes the adjustments needed for the mind transfer, Supergirl, Alex and Lena agree to go under quickly as Supergirl’s powers are fading from the effects of the solar eclipse.


When they awaken, they are in a dark forest. Though disoriented, they resolve to try to find Sam and Julia before they are overtaken by their Worldkiller personas. Sensing that they are being followed, Alex gathers tree branches with sharp ends for each of them. Seeing the approach of a figure, a dark Kryptonian demon appears and attempts to scare the heroes.


Standing their ground, the trio manages to chase the spirit away. When they are finally able to find Sam and Julia, they find them near catatonic and unresponsive to their words. Both women are experiencing memory loss and hallucinations of the various persons their evil personas have killed. They are finally able to get through to Sam by reminding her that she is a mother and that her daughter Ruby needs her. Sam awakens back in her body, only to discover that she’s in the Reign uniform in the middle of a closed eye ritual with the two other Worldkillers. Slipping away, she finds a control panel. She takes one of the program crystals and places it into the panel, causing the desert fortress to become uncloaked from DEO sensors. This awakens Purity and Pestilence from their concentration to see what Sam has done. Pestilence grabs Sam and punches her, knocking her down. This sends Sam back to the alternate plane and Reign takes control of Sam’s body once again.

When the DEO team discover the location of the desert fortress, they revive Supergirl, Alex, and Lena. Just before the DEO team is dispatched to the fortress to stop the Worldkillers, Winn tells Alex that he has a surprise for her. He explains that Alex rushes into battle against meta-humans all the time and that it’s about time she goes in prepared. He presents to her a body armor suit and experimental new gun.  Alex quickly changes into her new uniform and joins Supergirl, J’onn, Mon-El and Saturn Girl at the desert fortress as the confront the Worldkillers.


The Worldkillers are initially able to get the upper hand in battle, but both Supergirl and  Alex plead with Purity, asking that Julia please fight for control. Their cries work, and Julia is able to overcome Purity and regain access to her body. She and Pestilence battle one another. When Pestilence stabs Julia with her venom laced talons, Julia uses Purity’s sonic scream directly into Pestilence’s face. Once her scream is ended, they two Worldkillers fall to the ground dead. Their energy is then transferred into Reign, who flies off to safety. When she does, the desert fortress begins to crumble and collapse. Supergirl and team manage to fly out of the structure just in time.

Back at the DEO, Saturn Girl happily tells Mon-El that now that Pestilence is dead that there’s no chance of her becoming Blight. Because of this, her sister will not be killed after all. Mon-El is happy for her, but now seems conflicted in possibly returning to the future and leaving Supergirl behind again.

Supergirl apologizes to Lena for not trusting her and asks if they could put what happened behind them. They shake hands after Lena says yes. Once Supergirl leaves, James Olsen has a talk with Lena in which he admits to sneaking into L-Corp to find out if she was telling the truth about not having anymore Kryptonite. While initially offended, James continues, saying that he didn’t have the strength to go through with looking in her vault. He said that the Lena he knows has done nothing but good and is nothing like the rest of her Luthor family. He tells her that he trusts her and wants their relationship to move forward if that’s what she wants. Lena says that she very much wants a relationship with James, but that in order to do so, she must come clean too. She tells him that the Kryptonite she used on Reign really wasn’t left over from Lex’s term as L-Corp owner. She explains that she was able to discover how to create her own Kryptonite and that she used the manufactured substance to keep Reign sedated. James is aghast that  Lena has the means to create her own Kryptonite, but she reassures him that she doesn’t mean to use it against Supergirl or her cousin. She is upset, though, when told by James that Supergirl is the one who put him up to the infiltration assignment.

What Does This Mean for the Future?

Now possessing the strength of all three Worldkillers, Reign is even more deadly than ever. Trying to stop her and save Sam in the process has become even more difficult than before.

Conflicted by his feelings, Mon-El is starting to realize that his feelings for Supergirl may be too strong to leave behind. He is now seriously contemplating the possibility of leaving his wife and their life in the future together in order to stay in the present with his true love, Supergirl.

While still not a villain, the revelation that Lena Luthor can now create her own Kryptonite and is bitter at the fact that Supergirl put her boyfriend up to betraying her makes Lena a very dangerous person. If she’ll put these potential dangers aside and stay true to who she really is, is something we’ll have to wait to see.

Rating: 7/10

Final Thought: The episode was pretty adventurous and fun to watch. It did get a little hokey at times, as the whole mind travel plot rang very A Nightmare on Elm Street 3: Dream Warriors. That said, it was nice to see that Julia was able to overcome her fears and triumph over Purity, even if it cost her her life.

I’m also very interested in finding out what happens between Mon-El and Supergirl as the season draws to a close. Their romance is very soap opera-tinged, but as a fan of both characters, I’ve completely invested in seeing if their love will triumph, or if he will be forced to leave her again.

I’ve always felt that James Olsen was a boring filler character, even when he becomes the vigilante hero Guardian. Now that he’s dating Lena Luthor and becoming more involved with her loyalties, he’s beginning to become more interesting. I’m actually interested in seeing more of their relationship play out as well.

For the Reign storyline, I’m becoming a bit bored with it. Hence the lower episode rating score. It was fun for a while, but now things just seem dragged out. Add to the fact that I find Sam’s daughter Ruby very annoying, I’m hopeful that once the new season starts, we won’t be hearing any more of Reign or her brood for a very long time.

Follow us on Twitter, and Like us on Facebook! Subscribe to us on YouTube!

Join our Age of Social Media Network consisting of X-Men, Marvel, DC, Superhero and Action Movies, Anime, Indie Comics, and numerous fan pages. Interested in becoming a member? Join us by clicking here and pick your favorite group!


Create a website or blog at

Up ↑

%d bloggers like this: