Sam Three weeks after graduation, I'm lying on my bed scrolling through f*******: when the first message pops up. Hey Sam, have you heard from Tina? She's not answering anyone. It's from Jessica Martinez, one of Tina's friends. I stare at the message for a second, my thumb hovering over the keyboard. Why would Jessica think I'd know where Tina is? We're not exactly friends. I type back: No, haven't heard from her. Why? Before I can even set my phone down, another message comes through. This one's from Brandon Cole. Sam, do you know if Tina's okay? No one's seen her since graduation. My stomach tightens. Since graduation. I sit up, my heart starting to beat faster. I open my messages and see three more notifications. All asking about Tina. All saying the same thing—no one's seen

