“Tell the students to stay close to the carts,” she said. “Tell them again and again. They must not fall behind.”

“It wasn’t your fault,” he repeated. He wanted to hold her hand, give her a pat on the back, some reassuring gesture. But she was immortal, she was a Star. It would be presumptuous to touch her. It was enough for him, it had always been enough for him, that she was in this world. Sitting beside him on the same bench.

THE FIRST TIME the professor had seen Sparrow, she had been on her hands and knees polishing the floor just outside his office. He had opened his door to see a young woman bent over, rubbing the wooden planks with half a coconut husk. It was still daytime, but inside the long hallway with its narrow windows and dark paneling, it was dim enough for him to see her glow.

Professor Kang blinked. He saw Sparrow Chen, the servant girl. He also saw a shining form that conjured memories of perfect, long-forgotten days. His senses swam with visions of trees reflected in clear lakes, the fragrance of magnolia, the quick soft beat of golden feathers flashing between green banana palms. Then she had looked up, her features exquisitely and impossibly beautiful. Unquestionably not of this world.

How does one start a conversation with the supernatural?

“A Star,” she said, in response to his questioning gaze. “From the constellation of the Purple Forbidden Enclosure.”

Professor Kang’s words came out in an awkward rush. When he was a boy in Soochow, he told her, his family had lived next door to a Fox spirit. He had been friends with the Fox until he left for university in Nanking. On another occasion in Soochow, he had been strolling beside a canal early one morning and glanced up to see the figure of the Goddess of Mercy painted on a cloud. As the cloud moved across the sky, she turned her head slowly from side to side, looking down on the city as though she was inspecting it. He had watched until high winds scattered the cloud and the Goddess of Mercy dissolved into the sky.

“Fewer and fewer mortals can see us now,” the Star had said, her smile wistful. “Whether it’s to do with an open heart or random chance, who can say. But then, who’s to know why heaven allows any mortals to see us at all. I’m glad you’re one of them, Professor.”