When enigmatic freshman Amanda Valentino arrived at Endeavor High, she chose three people - Callie, Hal, and Nia - to guide her through the choppy waters of her new school. Except she didn't tell them about each other. When Amanda leaves, the three must reluctantly work together to figure out why. But once they start piecing together the cryptic clues that Amanda herself is leaving for them, they realize that everything they thought they knew about her is false. The more they dig, the mystery of where - and who - Amanda is deepens.

Chase Mitchels gets an email from Facebook saying he's been tagged in a post by Unknown. The post says, "In 24 hours, Chase Mitchels will be dead." Who is Unknown, and why is he after Chase? As each hour passes, Chase must fight to survive while Unknown hunts him down. Will he survive, or will Unknown kill him? Chase Mitchels, You've Been Tagged.