NE VERY hot day about noon, the midges started dancing above the tallest spruce tree on the island. Midges—not to be confused with mosquitoes—dance in vertical clouds and always in tempo. Millions and billions of microscopic midges rise and fall in perfect precision, singing stridently.

“The wedding dance,” Grandmother said, trying to look up without losing her balance. “My grandmother always used to say you had to be careful when the midges were dancing and the moon was full.”

“How come?” Sophia said.

“It’s the great mating day, and nothing’s safe. You have to be very careful about tempting fate. You mustn’t spill salt, or break a mirror, and if the swallows leave your house, you’d better move before sundown. It’s all a terrible nuisance.”

“Where did your grandmother ever get such dumb ideas?” asked Sophia in disbelief.

“Grandmother was superstitious.”

“What’s ‘superstitious’?”

Grandmother thought for a moment, and then she said that superstitious was when you didn’t try to explain things that couldn’t be explained. Like, for example, cooking up magic potions when there was a full moon and actually getting them to work. Grandmother’s grandmother had been married to a priest, who didn’t believe in superstition. Every time he was sick or depressed, his wife would cook up an elixir for him, but the poor woman was forced to do it in secret. And when it made him well, she had to pretend it was Innosemtseff’s Tonic that had done the trick. It was a great strain on her over the years.

Sophia and Grandmother sat down by the shore to discuss the matter further. It was a pretty day, and the sea was running a long, windless swell. It was on days just like this—dog days—that boats went sailing off all by themselves. Large, alien objects made their way in from the sea, certain things sank and others rose, milk soured, and dragonflies danced in desperation. Lizards were not afraid. When the moon came up, red spiders mated on uninhabited skerries, where the rock became an unbroken carpet of tiny, ecstatic spiders.

“Maybe we ought to warn Papa,” Sophia said.

“I don’t think he’s superstitious,” Grandmother said. “For that matter, superstition is old-fashioned, and you should always believe your father.”

“Of course,” Sophia said.

The swell carried in a big crown of twisted branches, as if some gigantic animal were wandering slowly in along the ocean floor. The air above the rock stood still and quivered with the heat.

“Didn’t your grandmother ever get scared?” Sophia said.

“No, but she liked to scare other people. She’d come in to breakfast and say that now someone was going to die before the moon set, because the knives were crossed in the drawer. Or she would have had a dream about black birds.”

“I dreamed about a guinea pig last night,” Sophia said. “Do you promise to be careful and not break any bones before the moon sets?”

Grandmother promised.

The odd thing was that the milk actually did go sour. They caught a stickleback in their net. A black butterfly flew into the house and lit on a mirror. And along toward evening Sophia discovered that the knife and the pen on Papa’s desk were crossed. She moved them apart as quickly as she could, but of course the damage was done. She ran to the guest room and banged on the door with both hands, and Grandmother opened it right away.

“Something’s happened,” Sophia whispered. “The knife and the pen were crossed on Papa’s desk. No, nothing you say can make it any better!”

“But don’t you understand?” Grandmother said. “My grandmother was just superstitious. She made things up because she was bored, and so that she could tyrannize her family...”

“Quiet,” said Sophia seriously. “Don’t say anything. Don’t say anything to me.” She left the door standing open and walked away.

The first cool of the evening arrived, and the dancing midges disappeared. The frogs came out and started singing to each other, while the dragonflies seemed to be dead. In the sky, the last red clouds sank into the yellow ones, making orange. The forest was full of signs and portents, its own secret written language. But what good did that do Papa? There were footprints where no one could have stepped, crossed branches, one red blueberry bush in the midst of all the green ones. The full moon rose and balanced on the top of a juniper bush. Now was the time for unmanned boats to glide out from their shores. Huge, mysterious fish made rings on the water, and the red spiders gathered wherever it was they had decided to meet. Implacable fate sat waiting just over the horizon. Sophia searched for herbs to make an elixir for her father, but all she could find were plain, ordinary plants. It is never clear which plants can be considered herbs. They are very small, presumably, with soft, pale stems. If possible, they should be slightly moldy and grow in swampy places. But how could you tell for sure? The moon rose higher and began its inevitable orbit.

Sophia shouted through the door: “What kind of herbs did she cook, that grandmother of yours?”

“I’ve forgotten,” Grandmother said.

Sophia came in. “Forgotten?” she said between her teeth. “Forgotten? How can you forget a thing like that? If you’ve forgotten, then what am I supposed to do? How do you expect me to save him before the moon sets?”

Grandmother put aside her book and took off her glasses.

“I’ve turned superstitious,” Sophia said. “I’m even more superstitious than your grandmother was. Do something!”

Grandmother got up and started putting on her clothes.

“Forget the stockings,” said Sophia impatiently. “And the corset, too. We have to hurry!”

“But even if we pick the herbs,” Grandmother said, “even if we pick them and make an elixir, he won’t drink it.”

“That’s true,” Sophia admitted. “Maybe we could pour it in his ear.”

Grandmother pulled on her boots while she thought.

Suddenly Sophia started to cry. She had seen the moon over the sea, and a person never knew about the moon. It can set all at once, on its own peculiar schedule. Grandmother opened the door and said, “Now you mustn’t say a word. You mustn’t sneeze or cry or belch, not even once, until we’ve gathered everything we need. Then we’ll put it all in the safest place we can find and let it work from a distance. In this case, that will be very effective.”

The island was bright in the moonlight, and the night was quite warm. Sophia watched as Grandmother plucked the head of a beach pea, picked up two small pebbles and a wisp of dry beach grass, and stuffed it all in her pocket. They walked on. In the woods, Grandmother collected a bit of tree moss, a piece of fern, and a dead moth. Sophia followed along silently, her nerves growing a little calmer with each item that Grandmother put in her pocket. The moon looked slightly red and was almost as bright as day. A path of moonlight led toward them over the water, all the way to the shore. They went straight across the island to the other side, and now and then Grandmother would bend over to pick some important ingredient. Large and black, she moved along in the path of the moon. Her stiff legs and her walking stick marched steadily forward, and she grew larger and larger. The moonlight rested on her hat and her shoulders as she watched over fate and the island. There was not the least doubt but what she would find what they needed to avert misfortune and death. It all found a place in her pocket. Sophia followed along right behind her and saw how Grandmother carried the moon on her head, and the night became utterly serene. When they were back at the house, Grandmother said they could talk again.

“Quiet!” Sophia whispered. “Don’t talk. Let it lie there in your pocket.”

“Good,” Grandmother said. She broke off a little piece of rotting wood from the steps and put it in with the rest, and then she went to bed. The moon sank into the sea, and there was no cause for alarm.

From that day on, Grandmother kept her cigarettes and matches in her left-hand pocket, and they all lived together happily until fall. Then Grandmother sent her coat to the cleaners, and almost immediately Sophia’s father sprained his ankle.