July 4, 2012, was a scorcher in Star City, West Virginia—a prelude to what would become the hottest month that year. While some escaped the heat by watching The Amazing Spider-Man or Magic Mike in the cool dark at the nearby Morgantown Mall or swimming in the Monongahela River, 16-year-old Skylar Neese was moping around her family's apartment, beyond bored. Feeling ditched by her friends who'd gone away together, she tweeted her frustration: sick of being at fucking home. thanks "friends", love hanging out with you all too.

"I said, 'Skylar, why don't you read a book?' " recalls her mother, Mary, sitting in the family room, gesturing toward the full bookcase. "She devoured the Twilight books. She was just getting into the classics. She loved Great Expectations."

With bright blue eyes (a gift from her mother), ivory skin, and a dimpled chin, Skylar was an honors student at University High School heading into her junior year, excelling in two subjects she couldn't stand: math and science. By July she'd already gotten a jump on the required summer reading: Susan Sontag's Regarding the Pain of Others and Saul Bellow's 1959 surrealist novel Henderson the Rain King, in which the protagonist speaks in pitch-perfect Twitter verse: "If I don't get carried away I never accomplish anything…Alone I can be pretty good, but let me go among people and there's the devil to pay." And every teenager's cri de coeur: "I want, I want, I want, I want, I want!" Skylar wanted to be out with her best friends. Before going to sleep that night she tweeted: stress will be the death of me.

The next day, Thursday, after working the evening shift at Wendy's, she went home, where her parents were watching television—Mary sitting in an overstuffed recliner and her father, Dave, lying on the couch. She kissed them both, and told them she loved them and that she was tired and going to bed.

The next time, the last time, they saw their only child was in a grainy black-and-white video. She was sneaking out her ground-floor bedroom window in the middle of the night, her purse over her shoulder, hair swinging as she hurried across the small parking lot to a waiting car. Watching Skylar climb into the backseat during those last few seconds of footage retrieved from the apartment building's security camera, there's an urge to call out to her, No! Don't go! But the door closes, the car pulls away, and she's gone.

If you were ever a 16-year-old girl, you have a war story. Even the luckiest, prettiest, most gifted, most popular girl has a scar somewhere. We've all taken aim. We've all been targeted. We are all every character in Lord of the Flies and Mean Girls, or any one of those trying to survive in The Hunger Games.

In an adolescent's game of thrones, one needs an ally, someone to fend off the slings and arrows of rivals and bullies. Skylar and Shelia Eddy had been close as kin since they were seven or eight years old. "Shelia didn't even knock on the door when she came over, she just came on in," recalls Dave Neese, a large, muscular, softhearted man with dark eyes and a butch haircut. Always bringing home strays, Skylar immediately took to Shelia, an only child of divorced parents. A slip of a thing, 100 pounds soaking wet, Shelia was as wild as the Appalachian Mountains around them. "Skylar thought she could save her," says Mary, an administrative assistant. "I would hear her on the phone givin' Shelia all kinds of hell: Don't be stupid!What were you thinkin'? On the other hand, Shelia was so much fun. She was always silly and doin' crazy stuff."

Their freshman year at UHS—the first school they attended together—Skylar and Shelia met Rachel Shoaf, a Catholic middle-school grad who had an older half brother. Where Shelia ran unsupervised, Rachel, also a child of divorced parents, came from a strictly religious home. That fall, the girls became a trio of best friends, with Skylar and Rachel each angling to be the one closer to Shelia, who reveled in her sway.

It's no accident that Girls and Sex and the City revolve around four friends instead of three. Three's a crowd, and four, or five, or more, against all mathematical reason, isn't. Any girl who's been caught in a social triangle knows this. She knows too the undercurrent of anxiety felt by all, recognizing that the degrees of love and the balance of power are always shifting. The problem, wrote the late Thomas Fogarty, MD, a respected family-systems psychiatrist and an expert on relationship triangles, "is that the lines (relationships) are fixed, closed, determinative of each other." Any action in one position forces a reaction in the others, so that "they find closeness difficult to maintain and…one person overlaps the other so that there is an indistinctness…It is difficult to tell what is self and what is the other person," leaving the third person at a distance—still inside, but at a remove, observing the closeness she longs to experience, and feeling abandoned.

Attractive in distinct ways, the teens were straight out of a CW Network casting call: Rachel was redheaded, tall, religious, a star in the school plays. Skylar, the brunette, was cherubic, spirited, loyal. And Shelia, sometimes bottle blond, sometimes raven haired, was game for anything, charismatic, sexual, the kind of beauty you'd see waving atop a float in a small-town parade. While they lived in different suburbs of Morgantown, they were living together virtually in the digital realm. They spent their waking lives posting, texting, tweeting, retweeting—having whole conversations in 140 characters, emoting in emoticons. As Skylar tweeted on April 4, 2012: twitter seems to like, swallow me, at times.