“I know what you did.”

Out of the corner of my eye, I see Abby freeze in her seat. I pretend to pay attention to my teacher reading about the fall of Czar Nicholas II, but all I hear is mumbling. Abby hands me the note again, which I open to find the words “Sit with me at lunch” scrawled underneath my message. I pocket the note.

Under normal circumstances, I wouldn’t even be within a foot of h...