No matter how hard Aris tugs on the lid, it doesn't move. Instead, a lock shimmers into view, with an alphabetical keypad and four spaces for entering letters. Looks like the dumpster is now password protected.

A flock of birds circles overhead. One drops a note written in black ink and in shaky penmanship, as if a bird wrote it while clutching the pen in its beak.

If you don't figure this out we will ATTACK you! And boy will it be SHARP! But we won't BILL you for it HARDY HAR HAR.

Then, below, in neater writing:

The answer you seek can be found in your school.