Not even the smallest clue gets past this preschool private eye! Just as Mitzi is about to enjoy a nice muffin her Dad made, her friend Max stops her in her tracks! He has a sneaking suspicion that there is something funny about this muffin -- so the two of them set off on an investigation... Kids and parents will laugh along as Mitzi, Max and their friends test the muffin for dodgy ingredients and come to their conclusion. What did Dad put in the muffin after all? Debbie Ohi's bouncy illustrations bring an extra layer of fun to Lauren McLaughlin's clever text.