Lu's got toothache. She has a dentist's appointment, but she hates going to the dentist and is trying every trick she knows to get out of going. Unfortunately her mum insists and writes a note to school.

Lu thinks she can get out of it, but a helpful friend drops her right in it. But, when at last she gets there, it turns out rather better than she thought. This book is part of the very popular series Siti's Sisters, featuring Siti and her group of friends, who are so close they call themselves The Sisters.