WARNING: The following contains major spoilers for "Rebirth," the Season 6 premiere of Supergirl.
Lena Luthor just took care of business. In "Rebirth," the Supergirl Season 6 premiere, she used the Kryptonian weapon Myriad on her brother Lex and mother Lillian, erasing their memories so they forgot the Girl of Steel's secret identity. As such, the Luthors have one less weapon to wield against Supergirl, at least for the time being.
Although Lex received a superpowered boost at the start of "Rebirth," he soon found himself at the mercy of Team Supergirl -- but not before he sent Kara to the Phantom Zone. Furious, Kara's sister Alex told him he would rot in a jail cell for what he'd done. In return, he threatened to reveal Kara's secret identity to the world, thus endangering everyone she cared about.
"I'm not going anywhere near a cell, unless you want me to reveal Supergirl's identity," he replied with a smirk. "She may be gone, but she still has an awful lot of enemies out there. It'd be tragic if Mama Danvers or your lovely Kelly Olsen were to become the target of one."
Before he could get much farther than that, Lena interrupted him by punching him in the jaw. However, his words clearly resonated with her, as she soon took drastic action. She waited until he was alone with their mother Lillian to strike, though, and found her opening when Lillian went to visit Lex in prison.
"I want it on the record that I'm resisting the urge to say I told you your obsession with the Kryptonians would end like this," Lillian sneered during her visit with him.
"I'm glad you held your tongue," Lex shot back, but -- before he could get in another jab -- a flash of purple light gave him pause. They turned to see what caused it, only to find Lena wielding Myriad at them. Without a word, she used it to erase their memories of Supergirl's secret identity.
Following this, Lena brought Myriad back to Alex and J'onn. "I came to return Myriad for you to safeguard it until Kara gets back," she said, leaving it in a briefcase on the table. "I have to admit, though, I did use it one last time tonight."
In response, Alex drew her eyebrows together out of concern. She exchanged a glance with J'onn, who raised an eyebrow, causing Lena to quickly elaborate. "On Lex and my mother and everyone associated with them," she clarified. "I wiped their minds of Supergirl's identity to protect you all."
"I understand now why keeping Kara's secret was meant to keep me safe," she continued. "But Alex, you really need to tell Kelly. She's your person, and you're going to need someone to talk to through all of this. If you don't, you'll just end up walling yourself off, and trust me, that won't do you any good."
Since Season 4, Lex has been a major thorn in Supergirl's side. He has used one elaborate plan after another in an attempt to stop her once and for all, all while dangling his knowledge of her secret identity over her head. Worse, he used this to drive a wedge between Kara and Lena, with the latter launching a near-villainous plan of her own in an attempt to get even with Supergirl for her "betrayal." While Lex will always remain a threat, he can no longer reveal Kara's identity to anyone else, which means her secret is safe once again -- at least for now.
Supergirl stars Melissa Benoist as Kara Danvers, David Harewood as Martian Manhunter, Chyler Leigh as Alex Danvers, Nicole Maines as Dreamer and Jesse Rath as Brainiac-5. New episodes air Tuesdays at 9 p.m. ET/PT on The CW.