Beware! It's Friday the 13th

Headmaster Mordred charges new student princesses "TEN-tee, twwwwenty pennies", not 7 tuition. His sister Lobelia designs lasses' costume with bells. Her niece Erica, not lad Eric, warns bells will scare dragons. Mordred fears Friday the 13th and dons lucky clothes - lacy bonnet, eel around neck. Students copy, but fire-breathing Snagglefahng chases Brother Dave.