They're coming again.

It's 4:24 a.m. on Oct. 13, and senior Mollie Segal's palms are pressed against the cold glass of her back door. Her eyes widen as she peers through the mist condensing around the spot where her nose, like her palms, is stuck to the glass. She is standing less than 15 feet away from, not just one ghost, but a whole Civil War platoon of them marching through her backyard.

They walk in groups, their faces blurred beneath their navy-blue Union caps, guns slung over their shoulders, just as they have every Oct. 13 at exactly 4:24 a.m. for the past six years. Each time, Segal has stared as they march, their brass buttons gleaming in the light of the moon. Tonight will be the last vigil she sits before she leaves for college, and she won't let the chance slip by: She's gathered her courage and chosen two ghosts she's going to approach. They're young and boyish, playfully pushing each other back and forth. Segal's hand clasps the latch. She slides the door open and steps forward into the thick night. They disappear.

"It was like you see in the movies," says Segal. But it was far from the movies - to her, the ghosts were as real as the disappointment she felt at losing her chance to speak to them. Her belief in the supernatural, solidified by her experiences, is something Segal shares with a growing number of teenagers in the U.S. today, according to Lynn Schofield Clark, author of "From Angels to Aliens," a book about teens, the media and the supernatural. For many of these teens, encounters with ghosts, spirits, tingles and the just plain weird are more frightening - and more fascinating - than anything that ever slunk across a movie screen."They looked human"

Segal experienced her first taste of the world beyond in sixth grade, when she returned from the Earth Day Festival in Washington, D.C. She had arrived home late and fallen asleep on the couch in her den. Groggily, she woke up and looked at her watch: 4:24 a.m.

Peering through the darkness with unfocused eyes - she wasn't wearing her glasses - Segal froze as her gaze met two tall, thin, pale, white figures "like stretched-out spaghetti people" hovering next to her dining room table. They motioned toward her window with their "spidery hands," displaying large, round palms and unnaturally long fingers. Beyond that, the details were blurry; Segal could see brow ridges, where their eyes should have been, but only the sockets remained. "They looked human, but I couldn't be sure," she says.

Terrified after meeting her first pair of ghosts, Segal sprinted up to her room and hid under her bed. Although the idea of ghosts still spooks her seven years after the incident, it also intrigues her. In addition to witnessing the annual night-time ghost marches, Segal frequently awakes in the middle of the night - always at 4:24 a.m. - to unnatural knockings on her windows and, once, to clothes falling off the hangers in her closet and being pushed aside as if somebody were searching for an outfit. "I was pinching myself to see if it were true," says Segal, still somewhat shaken by the experience.

Senior Marianna Ator experienced similar episodes when she lived in Fort Worth, Texas. When she was two or three years old, she says, her mother heard a loud thunk and rushed into her room only to find her lying on the floor, insisting that somebody had forcefully pushed her out of her bed, even though no one else was in the room. A few years later, her dad slept through his alarm, only to awaken when he felt someone - or something - shaking the bed. Ator was even more unsettled when the dial on her parents' radio alarm, which had always been set to NPR, rotated to a religious station one morning. At first, the family dismissed it and set it back. But two or three weeks later, Ator's parents were roused once more by a religious station - this one "clear across the dial."

Senior Chatise Scott-Webster has also had uninvited supernatural visitors in her house in the form of several small, white bird-like footprints that appeared on her carpet one morning. But the main visitor to the Scott-Webster house was a welcome one: the spirit of her great-grandmother.

"He's just checking up on us"

When Scott-Webster's great-grandmother passed away three years ago at the age of 82, the rims of all of the candles in the Scott-Webster household were coated with a filmy black substance. Scott-Webster's uncle swore that the substance indicated "bad vibes," says Scott-Webster. But once her great-grandmother's furniture, jewelry and other belongings were moved into the home, the black films disappeared, and with them, the tensions in the Scott-Webster household. "It was a good spirit presence," explains Scott-Webster, who has grown to feel more and more connected with her late-great-grandmother over the past three years.

Scott-Webster recounts how once, after a particularly upsetting day, she sat in her living room, surrounded by her great-grandmother's belongings. Suddenly, she started to shiver, but then, feeling a presence in the room, she was overcome with a wave of relief. "[My great-grandmother] had the most gorgeous silver-green-blue eyes," says Scott-Webster, "and I felt as if her eyes were looking at me and I calmed down."

The same feeling of release and peace envelops senior Rita Mitchell whenever she enters her late-great-grandparents' house in Sunbury, Pennsylvania - especially if she's in her great-grandmother's room, where one evening, she says, her great-grandmother spoke to her.

Mitchell was asleep in her great-grandmother's old-fashioned wooden-banister bed when she suddenly awoke with an unexplained compulsion to clean the house. She remembers an unfamiliar, but kind, voice saying to her, "It's not time to get up yet, go back to sleep."

Now, whenever Mitchell visits the house in Sunbury, she goes to the bedroom, sits down on the edge of the bed and starts the dialogue again. "I feel like I'm talking to someone there. It's not like talking to a wall or talking to a desk. There's definitely a conversation going," says Mitchell. "Or at least someone listening."

Freshman Dadee Ramos doesn't wonder if there's somebody listening - she knows that her grandfather is watching over her and her family. Twice now, his ghost has come to visit her, she says - although he's never said anything, only smiled. The last time, when she was staying with family in the small town of San Miguel, El Salvador, she knew in advance that he was coming.

The day before, she'd caught sight of a dark butterfly and later learned from her mother that it was an omen that somebody was going to die. The next night, she spotted him in her bedroom mirror. His clothes were all white, like the ones the family had dressed him in for the funeral, but he wore his customary white sombrero, too. She slowly turned around and smiled; he smiled back and then just "floated towards the door," she says.

The ghost disappeared through the wall, leaving Ramos with white dots hovering in front of her eyes - along with the comforting feeling that her grandfather understood her life and was there to help her. Ramos has overcome the fear she felt when she initially encountered her grandfather's ghost; now she's certain that "he's just checking up on us," she says.

Contacting the realm beyond

But Ramos wishes that she could check up on him, too. After watching TV shows in which people "go to the other side" or "cross the line," she says, she decided that she would call in to one. Even though her mother discouraged her, Ramos took the chance and telephoned a show, asking it to contact her grandfather for her. The show said it would try, but couldn't promise anything, says Ramos. Nothing came of the call.

Mitchell has also tried to create a stronger connection with her great-grandmother's spirit. She's become increasingly interested in her family's history, and the last time she visited the house in Sunbury, she used up three rolls of film, taking photographs in all the rooms and close-ups of different objects her great-grandparents had left behind.Although efforts to reach into the realm beyond are often met with skepticism, Clark emphasizes that the supernatural is becoming more accepted in American culture. She explains that contemporary teens are more open to listening to, experiencing and seeking out supernatural experiences.

Nevertheless, Segal is usually greeted with disbelief when she describes her encounters to others. "All through middle school," she says, "I was the weirdo, the crazy kid who saw dead people." Her father is certain she is on drugs, although her mother and her brother believe her accounts, she says.

But Segal has learned to ignore the antagonism. She is confident in the reality of her experiences. "It's that one thing that I have that a whole bunch of other people don't have," she says.

Although her encounters may distinguish her from the living, they bring her closer to the thin line that runs between what is real and what, in the silence of the night, might just be an illusion.