Mrs. Albright, the veteran kindergarten teacher, thought she was losing her mind. Test scores, however, were rising. Little Elena had started reading chapter books. A boy named Marcus, who wouldn't hold a pencil, was now writing sentences about rocket ships.

He was the best teacher Moss Creek had ever seen, and not a single soul had ever sat in his classroom.

She stepped out, not with anger, but with tears streaming down her face. "You're the Moonlight VPK," she whispered.

It started five years ago, after his wife left, taking the dining room table and his sense of purpose. Virgil had been wandering the school's darkened halls when he noticed a kindergarten cubby overflowing with uncorrected worksheets. A little girl named Elena had drawn a sun that looked like a fried egg and written "I am not smart" in shaky letters across the bottom.

What she saw was not a janitor mopping. It was a tall, weary man in gray coveralls, sitting cross-legged on a rug in the dark, a flashlight under his chin. Around him, he had arranged twenty little chairs in a semicircle. He was holding a puppet—a sad-looking raccoon made from a discarded oven mitt.

The next fall, the school board approved a new position: Night Custodian of Curiosity. Virgil Paul Kincaid got a tiny classroom in the basement, no windows, but a door that opened directly onto the playground. He taught from 10 PM to midnight, for children whose parents worked late shifts, for the ones who felt like rocks during the day.

Virgil Paul Kincaid—called VPK by everyone except his mother—was a third-shift janitor at the county elementary school. By day, he slept. By night, he pushed a mop across linoleum floors that still held the ghostly echoes of children's running feet. But Virgil had a secret.

The next night, there was a new worksheet. And a note: "Mrs. Albright says my letters are messy. Can you help?"

"Exactly," he said, nodding. "And that means you can shine too. Even when you feel like a rock. Even when nobody's watching."

Mrs. Albright's thermos slipped from her hands. It clattered to the floor.

Virgil found a red pen. He corrected the worksheet, drew a smiling face next to the fried-egg sun, and wrote: "You are a scientist. Scientists know that the sun can be anything we imagine."

And on the first night, twenty little chairs were not empty.