Lexy was still in her school uniform, but in less than ten minutes she was supposed to be wearing her best dress for dinner with the Bottles’ important houseguest. What was his name again? Jupiter something. He was a famous writer and philosopher in town to give a public lecture at the university as part of the Winter Fair. Lexy’s family had won a raffle, which meant they’d got to host their very own visiting personage, and they had been assigned Jupiter Whatshisname.

Lexy’s mother, Hazel, was taking her responsibilities as host very seriously. For far too long, she’d said, she had simply been seen as the flower-power, hippy-dippy wife of the local yoga teacher. No matter how hard she tried, Hazel had never appeared quite like other, normal mothers. She had never hosted a successful dinner party (the last one had featured bean stew and group chanting). She wore the wrong things. She had crazy hair. She went barefoot in summer, and in winter sometimes wore homemade skis to go shopping. She smelled of patchouli and herbal tea. She had never ironed a sheet in her life.

Until this week. This week, Hazel Bottle had declared, their houseguest was going to sleep on clean, ironed sheets, and in the morning his toast was going to be served in one of those little metal racks. Everything was going to be normal, just like it was in other people’s houses. And Lexy was not going to ruin it by being late, or by letting any of her remedies catch fire, or by making the whole house smell of burnt clove and scabious ointment, and she was going to tidy up her room and remove all her medicinal plants from windowsills around the house, and make sure the new kitten, Buttons, didn’t do anything too embarrassing. . . .

Lexy’s mind returned to the three drachms of powdered water lily in the jar in her school bag. Culpepper’s Herbal, a book Lexy was studying for yet another one of her tests, said that the herb “cools and moistens,” just like the moon itself. Lexy was going to use the water lily to make a new remedy for sports injuries and battle wounds. Her friends Effie Truelove and Wolf Reed always needed things like that. Lexy had also promised her friend Maximilian that she would make him some enchanted eardrops to enhance the sound of music. And Raven had asked for some magical hoof balm for her horses. It was going to be a busy weekend.