A teen girl's (guest star Azura Skye, 28 Days, Zoe...) obsession with Lex (Michael Rosenbaum) turns life-threatening when invisible attacks in Luthor Mansion pits Clark (Tom Welling) against an undetectable enemy. Meanwhile, Clark is thrilled when Lana (Kristin Kreuk) looks to him for companionship after Whitney (Eric Johnson) inexplicably pushes her away.
Allison Mack, Sam Jones III, Annette O'Toole and John Schneider also star. D.J. Caruso directed the episode written by Michael Green & Mark Verheiden.

Lex is being stalked by an invisible entity that threatens him and almost kills a bathing Victoria. Suspicion falls on Amy, the daughter of one of the household staff. She is dangerously obsessed with Lex, to the point of having a shrine of him in her room. Lex finds out and insists that the family move out. It turns out that the villain is Amy's non-entity of a brother, who has distilled an invisibility potion from krptyonite-mutated roses. He attacks Lex when the family is turned out, but Clark intervenes and manages to knock him out. Meanwhile, Victoria and Lex are putting together a plan to bring down Lex's father, but Victoria seems to have a scheme on the side that involves a bio-tech firm, Cadmus Laboratories. And Whitney is growing distant from Lana due to the poor health of his father, which drives Lana over to Clark.

Clark: Have you ever got information that you wish you hadn't?
Lex: In my experience I've found you can never have too much information.

Clark: Lana, have you ever seen the sunset from my loft?
Lana: Yes...Ahem, but that's the great thing about sunsets. They're unique. You always see things you've never noticed before.

Nell: Lana, you still out here...? (interrupting Clark and Lana's almost kiss) Clark, do you have the time?
Clark: No, but I'm guessing it's late.
Nell: Smart kid.

Jonathan: Clark, you know you can't donate.
Clark: I know, dad but what am I supposed to tell her?
Martha: Kent: That you have a problem with needles, which you technically do.
Clark: Great, not only do I lie, but I look like a wuss.

Lex: Napoleon's mother couldn't make it to his coronation. But when he commissioned it, Napoleon told David to paint her in as if she were there, right in the center. Even though she couldn't be there physically he brought her into his life through sheer force of will. There to share in his greatness.

Clark: No, I think I'll play it by ear, you know, fly by the seat of my pants...
Pete: Clark, you're not the flying type.

Pete: "Have you seen the sunset from my loft?" You actually said that (to Lana)?

Lana: That's the thing about Clark Kent: he's not always there when you want him...but he's always there when you need him.

Lionel: Empires are not brought down by outside forces - they are destroyed by weaknesses from within.

Lex: (to Lionel) LuthorCorp is your company. I'm just one of its expendable employees. As you made abundantly clear when you exiled me to this charming cow-town.

Clark: I can't see it.
Lex: What are you, part bloodhound?
Clark: I live on a farm. I'm good at seeing needles in haystacks.

Lionel: Lex, you have disappointed me.
Lex: Hi, Dad. Nice to see you too.

(checking out the invisibility stuff)
Clark: You know what you'd be if you rubbed this stuff all over your body?
Chloe: Naked?

The Palmer family works at the Luthor mansion. Amy and Jeff are the two Palmer children who help their mother around the house. While Lex Luthor and Victoria Hardwick are getting cozy in the mansion, it is obvious that Amy is jealous, since she constantly gives Victoria dirty looks and even "accidentally on purpose" spills a drink on her. We also see that an invisible form is destroying things around the manor. Later, Troy, one of the popular school jock teases Amy about the fact that she works as "the help" for the Luthors. Her brother Jeff tries to stand up for her. Troy goes to the shower room where both Clark Kent and Pete Ross are there to witness an invisible form attack Troy.

Later, while Clark is visiting Lex at the mansion, he finds Lex searching for a watch that his mother gave him before she died. Clark uses his x-ray vision, but is unable to locate the watch anywhere in the room. Later, we see Victoria is taking a bath, and suddenly, the same invisible form attempts to drown her.

Clark realizes something is wrong and rescues Victoria and realizes it is the same invisible force that attacked Troy in the shower. Clark discusses the recent events with Chloe Sullivan and they realize that it must be Amy. When Clark sees Amy at "The Beanery", he uses his vision to see that Amy is wearing the watch Lex was looking for on her wrist. He tells Lex about this, and Lex then searches Amy's room at the mansion. They find a shrine to Lex that she was keeping, and Lex asks the Palmer family to leave.

However, that night, after they have left, Lex is attached by the invisible force, but naturally, Clark saves the day, and we realize that it wasn't Amy, but her brother Jeff that was creating all the attacks.