Mary Woodvine

The Portwenn Players dance is being held in the village. Louisa buys two tickets and invites Martin along, but as dancing and social occasions are not his thing he turns her down. Louisa then invites Mark instead. He is over the moon and asks Martin's advice on his lack of success with the opposite sex.

Louisa is a candidate for the head teacher's job at Portwenn, but thanks to Martin the odds seem stacked against her. There is an outbreak of a highly contagious skin infection at the school and Martin is initially confounded, until his brilliant diagnostic skills uncover the source.