Clark: [discussing Clark's biological mother] I wish she could've met you. To see what a great mom I have.
Martha: She knows, Clark. A mother's love never dies.
At Excelsior Academy, teacher Mr. Woodruff summons Lionel Luthor, who finds a young Lex sitting on a balcony in the rain, cradling a bundled blanket he calls Julian. Lionel says Lex must come to terms with Julian's death, then grabs Lex's arm, causing his son to drop the blanket. Lex cries out Julian's name, while in the present, Lex again cries out for Julian, until he's found by Lana and broken out of his trance.
The following day, when Lana arrives at the Kent farm, Clark informs her that Jonathan's cardiologist sent him to Metropolis for additional tests, leaving Clark to pick up the slack. Lana, in turn, tells Clark that while dropping off the Talon payroll, she found Lex yelling for "someone named Julian." Clark explains that Julian was Lex's baby brother who died of SIDS, and that the last time Lex had a breakdown, Clark found him singing to a blanket and calling it Julian (Shattered). At the mansion, Lex, figuring Clark learned about his "nocturnal adventure" from Lana, dismisses it as harmless sleepwalking and insists to a concerned Clark that he can take care of himself. That night, Lex drives up to the Summerholt Institute, unknowingly followed by a superspeeding Clark. Inside, Lex informs Dr. Garner (Delete) that his nightmares are becoming more frequent and are disrupting his waking life, but Dr. Garner calls the nightmares "spontaneous memories" and explains that the treatment is working. In another part of the Institute, Lex, stripped down to his shorts, is lowered into a tank of green liquid, and with guidance from Dr. Garner, relives his twelveth birthday. In a room of the mansion decorated with balloons, twelve-year-old Lex sits alone, crying, when Lionel enters and notices that no one has come to Lex's party. Consoling his son, Lionel hands him a present that turns out to be a lead box (Metamorphosis) from Lex's mother Lillian, who's pregnant and resting. Lionel explains that the box was forged from the armor of St. George the dragon slayer, and that St. George defeated a "particularly fierce dragon" after placing his fears and doubts into it. Lionel continues that when people are cruel to him, Lex can put his own fears and doubts into the box, while in the present, Clark uses his x-ray vision to spy on Lex and Dr. Garner. Outside the Institute, Clark confronts Lex about working with Dr. Garner, warning that participating in Dr. Garner's research could kill him, but Lex is insistent upon retrieving his lost memories.
At LuthorCorp, Clark visits Lionel and tries to persuade the millionaire to shut down the Summerholt Institute before Lex remembers the lost seven weeks, pointing out that Lex could uncover the truth about Lionel's parents. However, Lionel argues that Clark is the one who doesn't want Lex to regain his memories, and plays the video surveillance from Belle Reve in which Lex admits he knows Clark's secret (Asylum). At the mansion, Lionel tries to talk Lex out of working with Dr. Garner, until Lex stops and remembers something. In the past, twelve-year-old Lex spies on his parents through a partially-opened door, watching as Lionel holds baby Julian and tries to get Lillian to hold their infant son as well. Lionel declares it unnatural for a mother to not want to bond with her child, but Lillian, accusing Lionel of chipping away at Lex's spirit, predicts that Lionel will pit their sons against each other and make them fight for his affection. When Lillian finally takes Julian from her husband, Lionel declares that Lillian needs some alone time with her son, then notices Lex peeking through the door. In the present, Lex cries and tells his father "it was an accident", genuinely confusing Lionel. In another memory, Lionel finds Lex standing over Julian's crib, then finds that Julian is dead. Lionel furiously asks what Lex has done and backhands him violently, while in the present, adult Lex falls to the floor in reaction. Lionel offers to call a doctor and warns that Lex is playing with fire, but Lex asserts that he's fine and tells his father to get out. Lionel arrives at the Kent farm and thanks Clark for informing him of Lex's activities, but says that Lex has decided to accelerate his treatment due to the "collective meddling" of Clark and Lionel. At Summerholt, Clark asks about Lex, but is weakened when he gets too close to the tank of green liquid. While Dr. Garner's team strips Clark down to his shorts, Dr. Garner speaks with Lionel via cell phone, agreeing that Lex will no longer receive treatment from Summerholt now that Lionel has held up his part of their deal.
Shortly after talking with Dr. Garner, Lionel arrives at Summerholt and watches as Clark is suspended above the tank, just as Lex also arrives at Summerholt and speaks with the receptionist, who reminds him that his session was cancelled and tells him Dr. Garner is at a seminar. Stepping away from the desk, Lex calls Lionel, and lies that his treatment worked and he remembers everything. Lionel leaves to meet with Lex, instructing Dr. Garner to wait for him to get back. However, Dr. Garner orders his team to lower Clark into the tank anyway, asserting he doesn't wait for anyone, then proceeds to guide Clark through his earliest memory. In the memory, Jor-El and his wife, Lara, place their infant son into the spaceship, while Jor-El assures Lara that Kal-El's destiny is set. Lara says goodbye to her "sweet Kal-El", then she and Jor-El seal the ship using the octagonal key. In the present, Clark repeatedly screams Lara's name, then has a reaction to the liquid and begins shaking. Dr. Garner refuses to let his team pull Clark out of the tank, until Clark's shaking becomes more violent and the surrounding equipment sends off sparks. In the waiting area, the ground shakes and the alarm sounds, interrupting Lex and Lionel's conversation. Reaching the memory lab, Lex finds Dr. Garner on the floor, then picks up a nearby pipe and smashes the tank, emptying it of green liquid.
That night, Lex checks in on Clark in his loft, and asks what Clark was doing at Summerholt. Clark replies that he was trying to save Lex from a big mistake, but Lex reminds his friend that he told Clark to let it go and that Clark went so far as to get Lionel involved. Clark counters that Lex tries so hard not to be like Lionel, but the more Lex and Lionel fight, the more Lex becomes like Lionel and the more people are hurt. Lex insists he's nothing like he's father, and that he would never sacrifice Clark or anyone else he cared about just to bring down Lionel. When Clark inquires why Lionel hates Lex so much, Lex doesn't answer, but instead, tells Clark to take care of himself and turns to go. However, Lex stops suddenly and recovers another memory. In the memory, young Lex finds Lillian standing over Julian's crib, holding a pillow. When Lex sees his baby brother dead, Lillian tells him "Julian's happy now" and staggers out of the room. In the present, Lex assures Clark that he's fine and leaves, then the following day, Lex, visiting Lionel at LuthorCorp headquarters, informs his father that Lillian was the one who killed Julian, not Lex. Upset, Lionel refuses to let Lex desecrate Lillian's memory, but Lex angrily continues that he blames Lionel, since Lillian wanted to save Julian from Lionel's "particular brand of parenting". When Lionel inquires why his son took the blame, Lex replies that he knew Lionel wouldn't let anything happen to his sole remaining heir, but Lillian would've been "the lamb to the slaughter". Lionel, immediately filled with regret, says that things would've been different between them had he known, and Lex agrees that Lionel might've actually loved him, before leaving. Meanwhile, back in Clark's loft, Martha checks on Clark, who assures her that his secret's still safe. He tells her his biological mother's real name, explaining that as part of his earliest memory, Lara worried about him being loved. He adds that Lara wasn't a monster like Jor-El, but can't believe he forget about her. Martha replies that he didn't, revealing that his first word was 'Lara' and she and Jonathan could never figure out what it meant, until now. Clark wishes that Lara could've met Martha to see what a great mom he has, but Martha assures him that Lara knows and that a "mother's love never dies".