Twenty-One: The Truth Hurts.

A big Greyhound huffed in the parking lot of the Lancaster bus station, its final destination, Philadelphia, emblazoned above the windshield. Emily tentatively climbed aboard breathing in the smell of new upholstery and heavy-duty bathroom cleaner. Even though she'd only spent a few days with Lucy and her family, the bus seemed jarringly modern, almost monstrous.

Emily had barely said a word to Lucy after Lucy admitted that Wilden had been her dead sister's old boyfriend. Lucy had repeatedly asked Emily what was wrong, but Emily said she was fine—just tired. What could she say? I know your sister's old boyfriend. I think he really might have killed Leah. There's a hole in the back of someone's yard where he might have dumped her.

Her brain had been on warp speed over since, circling memory after memory of that horrible time. The day after Ali vanished, after their talk with Mrs. DiLaurentis, Emily and her friends went in opposite directions. Emily had passed right by the big hole where they'd eventually find the body.

The workers, she remembered, had been filling the hole with concrete that very day. All their cars were along the curb next to the DiLaurentises' lawn. There was one at the end that she'd studied for a second or two, wondering where she'd seen it before. it was an old black sedan, like something out of a sixties or seventies movie. It was the same car that screeched up to the Rosewood Day Lower School curb the day Ali bragged to everyone that she was going to find a piece of the Time Capsule flag. After his fight with Ian, Jason DiLaurentis had yanked open the passenger door to that car and slumped inside. It was the same car that chugged outside the DiLaurentis house the day and the others tried to steal Ali's flag. And here it was in her memory again, looming at the DiLaurentises' house the day the concrete covered up that body for three long years. That car belonged to Darren Wilden.

The bus pulled away a few minutes later, the green fields of Lancaster disappearing behind them. There were only four other passengers, so Emily had a row to herself. Spying an outlet near her feet, she leaned down, plugged in her cell phone, and switched it on. The screen glowed with life.

Emily had to do something about what she'd learned, but what? If she called Spencer, Hanna, or Aria, they'd tell her she was crazy for thinking Ali was alive and for following A's instructions to go to Amish Country. She couldn't call her parents, either—they thought she was in Boston. And she couldn't call the police—Wilden was the police.

It was incredible that Wilden had really once been Amish. Emily knew very little about his life, only that he'd been a rebel at Rosewood Day but then had reinvented himself as a cop. It probably wouldn't take too much effort to find out when Wilden had left the community and started school at Rosewood Day, though, and when he spoke to Emily and the others in the hospital, he'd mentioned that he'd lived with his uncle in high school. According to Lucy, Wilden had convinced Leah, Lucy's sister, to leave the community as well. Maybe when she refused, he'd gotten angry…and made plans to do away with her for good.

Wilden could have talked to Ali about her secret dreams to run away since he and Jason were friends. Wilden might have even promised Ali to help her run away for good, sneaking her out of Rosewood the night she went missing. He dumped a body into the hole in the DiLaurentises' backyard, making it look like Ali had been killed. But the body in that hole didn't belong to Ali. It belonged to the girl who broken Wilden's heart.

Horribly, it all fit. It explained why Leah had never been found. It explained why Ali showed up in the woods last Saturday and why Wilden was dissuading the police force from investigating the possibility that Ali was alive—if they realized it wasn't her body in that hole, they'd have to figure out whose body it was. It was why Wilden didn't believe in A and didn't buy that Ian knew a secret about what happened that night. A had been right all along—there had been a secret. But it wasn't about Ali's death. It was about who had been killed in Ali's place.

Emily stared at the graffiti someone had drawn on the wall of the bus under the window. Mimi Luvs Christopher. Tina Has A Fat Ass. There was even a sketch of two fat butt cheeks next to it. Ali was out there, somewhere, just as she'd always known. But where had she been all this time? It seemed implausible that a seventh grader could survive on her own. Or perhaps she'd known someone who'd taken her in. Why hadn't she contacted Emily to let her know she was okay? Or maybe she hadn't wanted to contact anyone. Maybe she'd decided to forget her entire life in Rosewood, even her four best friends.

Emily's phone beeped, signaling three unread texts. She scrolled through her inbox. Two were from her sister Carolyn; both subject lines read People Survey. Aria had sent a text too; its subject line said We need to talk.

An old woman at the front of the bus coughed. The bus rolled past a farm, and the cabin temporarily smelled like manure. Emily moved the cursor from text to text, trying to decide which to read first. Just then, her phone pinged again, this time with a text from an unknown number. Her pulse raced. This had to be from A. And for once, Emily couldn't wait to know what A had to say. She pressed read immediately.

It was a photo text. The picture was of a bunch of blurry papers fanned out on a table. The top document was titled Alison DiLaurentis Disappearance: Timeline. The paper below it said Interview, Jessica DiLaurentis, June 21, 10:30 P.M. Another paper had a crest of something called the Preserve at Addison-Stevens, with the last name "DiLaurentis" shown. A red stamp on each of the papers said Property Of Rosewood Police Department. Evidence. Do Not Remove.

Emily gasped.

Then, she noticed a final piece of paper peeking out from underneath the others. Emily squinted until her eyes hurt. DNA Report, it said. But Emily couldn't read the results.

"No," Emily moaned, feeling like she was going to explode. Then, as the bus went over a bone-jarring bump, she noticed an accompanying note with the photo.

Wanna see for yourself? The evidence room is in the back of the Rosewood police station. I'll leave a door open. —A