Prue and Phoebe are visiting an occult book shop. Phoebe has an upcoming job interview and wants a good luck charm. Tanjella, the proprietor, is anxious to close before midnight. The next day is Friday the 13th and Tanjella tells skeptical Prue and Phoebe of a convergence of negative energy. At midnight, the clock strikes 13 and the sisters leave. A massive cloud of smoke covers the area around the store. The demon Barbas appears out of the cloud as they drive away and slides through the closed door. Barbas gestures and names Tanjella's greatest fear: being buried in an earthquake. The shop shakes, and things fall down everywhere. Tanjella tries to move, but can't; Barbas tells her she's paralyzed by her fear. Tanjella falls down dead, her hair turned entirely white.
Phoebe talks to Piper and notes that Prue never says "I love you." Piper is planning a superstition-themed fund raiser at Quake. Piper is adhering to lots of superstitions, but Prue is typically skeptical.
Andy shows up and asks after Prue as Phoebe and Piper leave the manor. He notes the death of Tanjella and two others who died like her. Prue had been Tanjella's last customer. The three victims were all single young women involved with the occult. After he leaves, Prue consults the Book of Shadows and finds the page on the Demon of Fear. The page is in her mother's handwriting. Prue meets Piper at Quake and tells what she found: Barbas must kill 13 single female witches to free himself, and can only do this on one Friday the 13th every 1300 years. He kills by exploiting a witch's greatest fear. Prue remembers Piper is wary of flying, and that Phoebe is afraid of being stuck in an elevator. Piper tells Prue to stay away from pools; ever since their mother drowned she's been afraid of drowning as well.
Phoebe interviews at SWA Properties, a real estate firm, and easily lands the job. Her boss, however, wants her to cover if her husband calls. The boss leaves with her lover.
Barbas visits a witch named Zoe. However, Zoe has been expecting Barbas, and claims to have no fear. However, she still fears fire; she merely suppressed it over the years. Barbas causes flame to shoot out of one of Zoe's candles and turn into a ring of fire. Prue had found her name on a flyer that Tanjella had given her and enters Zoe's apartment, but she is a moment too late. Fearing that she might be suspected of involvement in the murders, Prue calls 911 and heads for home. Andy notes that Zoe is the fifth woman to die this way, implying one other besides Tanjella. Darryl has found Prue's name on the doorman's log.
The sisters are dining at Quake and Prue is trying to discourage Piper from relying on superstition. Phoebe finds a ladybug on a leaf and notes something Grams once told her: that a ladybug can lead you to your ideal mate. The ladybug lands on a young man on a nearby table, Lucas. After Prue and Phoebe leave, Lucas comes over and asks Piper out.
Phoebe is conflicted about lying to her boss's husband. She flips the good luck charm, but it lands standing on its side. She has a vision of Prue drowning in the shower. She calls the manor, but Prue doesn't answer. Prue is in the shower and sees Barbas as he appears. The shower begins to fill with water. Her powers don't work because of her fear. At last her head is underwater. Andy and Darryl appear at the manor to ask Prue about Zoe. They hear her scream and kick the door in. They enter the bathroom, but Barbas disappears. The water recedes and Prue is saved. Prue is reticent and tells the cops that she had soap in her eyes. Andy thinks that Prue might have been the next victim. Phoebe reaches the manor and the cops leave. Phoebe notices that a lock of Prue's hair has turned white indicating just how close Barbas came to killing her.
Prue and Phoebe consult the Book of Shadows. Prue notices the attic smells of sandalwood, a scent that their mother had worn, and finds a new line on Barbas's page: "To let go of your fear, trust in the greatest of all powers". Prue says this line wasn't present before, and that she feels their mother's presence. Phoebe says "I love you" and Prue only says "me too." It turns out "I love you" was the last thing Prue said to her mother before she died.
The husband of Phoebe's boss appears at her desk. He asks where his wife is and Phoebe is unwilling to lie. She says nothing definite and instead tries to quit her job. The husband knew about the affair but had been in denial. As he leaves, a client calls, wanting to bring Phoebe out to a large estate. Phoebe goes, only to find that the "client" is, in fact, Barbas. There is a pool on the grounds. Phoebe's greatest fear is losing a sister, not elevators as she thinks. Barbas ties Phoebe up. Barbas calls Prue using Phoebe's voice. Piper is having a run of bad luck. In the kitchen at Quake, she tries to cast a spell, but the burning sage stick only sets off a smoke alarm. She ends up scalding her hand when she attempts to neutralize the sage stick.
Piper has dinner with Lucas. After a while, she thinks Lucas is too good to be true. He mentions pictures of his nieces, and she freezes him. She checks out his wallet and finds that he is telling the truth, but feels wrong about choosing him based on superstitions. She unfreezes him and claims to be superstitious, immediately turning him off.
Prue reaches the estate. Barbas shoves her into the pool. Prue, however, sees the ghost of her mother in the pool. Patty tells her that the "greatest power" named in the Book is love. Patty takes Prue's hand and she returns to the surface. Her power restored, she flings Barbas back. She declares that she is not afraid and Barbas vanishes in a cloud of red embers. Prue can once again say "I love you." As midnight chimes, Prue is reading Barbas's page in the Book of Shadows. New writing appears: "Thank you for letting them into your heart."