Orion lived in Skyline City, where buses hummed softly and gardens grew on rooftops. He was six, and he loved two things most of all: drawing and wondering.

He wondered about yesterday. He wondered about tomorrow. He wondered what the world looked like before his street, before his school, before even the first sandwich.

Orion also had two sisters.

Lina was older and careful. She kept her hair in a neat bun and her thoughts in neat rows.

Mira was older too, but not careful at all. She had wild curls and wilder ideas.

The three of them shared a secret in the back room of their home, behind a curtain printed with tiny stars.

It was called the Clockwork Doorway.

It looked like a tall silver closet. The door had a round window like a porthole. Pipes curled around it like metal vines. A tiny screen blinked with green numbers.

“We made it,” Lina said, and her voice tried to sound calm.

“We *invented* it!” Mira sang, doing a little dance.

Orion stared, his mouth open. “It’s a real time machine?”

“It’s a real time machine,” Lina said.

Orion’s tummy felt wiggly. “Will it be loud?”

“Only like a purring cat,” Mira said. “Except the cat is a closet.”

Lina held up a small notebook with a red cover. “We need rules. We do not touch things that could change history. We watch, we learn, and we help only when it’s safe.”

Orion nodded fast. He liked rules when he was nervous.

Mira held up three bright badges. Each badge showed a picture of a little hourglass.

“These will bring us home,” she said. “If we get lost, we press the badge and say, ‘Back to our time.’”

Orion clipped his badge onto his shirt.

Lina typed on the blinking screen.