"Okay, tell me what I did wrong now." I cross my arms and stand behind Isabelle.

Her head is buried in her locker, and she's mumbling incoherently. "The list of what you didn't do is shorter." She straightens and turns around.

I laugh, but she doesn't so much as crack a smile. I sigh. "Seriously, what's wrong?"

"Nothing." She shoves her books in her bag and zips it closed before hefting it over her shoulder. "I have to get home."

When ...