In this 4th installment of the Chronicles of the Monster Detective Agency, fledgling Monster Detective Will Allen has conquered monsters, triumphed over bullies, and even survived his mother's cooking, but now he faces a challenge that all of his cleverness and bravery are powerless against - dealing with GIRLS!

And even if he overcomes THAT challenge, can Will rise to the occasion and save himself and his friends from yet another crop of living nightmares when his special tools, the RevealeR and the MonsterScope, suddenly lose their monster-fighting powers?