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Prologue: The Worldline That Ran Late

The day Hoshino Yoruichi was late, the monitor in the Worldline Observation Club lit up.

The screen read: If he arrives on time, he will pick up a dropped key at the foot of the stairs. If he is late, the key will roll into the drain, and the clubroom will lose a future member.

He stood in the doorway, looking at that line, and decided to see his lateness through to the end. The clink of the key rose from the drain, as if the world were applauding.

Chapter One: A Clubroom for Three

The clubroom held only three people: the president, Kagami Hana; the vice president, Shirayuki; and Yoruichi, who had just been chosen by being late.

"Rule one," Kagami Hana said, tapping the monitor. "Do not observe yourself. Rule two: if you do observe it, pretend you saw nothing. Rule three: after school, the monitor must be switched off, or the worldlines will treat this clubroom as a hub."

Yoruichi nodded. He had already seen his own name flicker in the corner of the screen, and at once he moved his eyes to the ceiling. There was a ring of water stain there, like the map of another worldline.

Chapter Two: A Death Notice on the Rooftop

The death notice on the rooftop appeared on Wednesday.

The monitor showed that at 17:04 Yoruichi would vanish from the outside of the railing. Two branches: someone catches him, or no one does. Of the people who might catch him, one line was Kagami Hana, and one line was Shirayuki.

"This is why you cannot observe yourself." Kagami Hana turned the screen's brightness down. "Observation turns a notice into an invitation."

Yoruichi still went up to the rooftop at 16:50. The wind was strong, as if someone were rehearsing.

Chapter Three: Two Monitors

The day two monitors were carried into the clubroom, the door began to be knocked twice at once.

Kagami Hana came in from the left, Shirayuki from the right, and both of them said, "I came to pull you back." Yoruichi stood between them and felt himself folded into two letters.

"We can only keep one," he heard himself say.

Both monitors lit up with the same face—his face, on the rooftop, alive and not alive at the same time.

Chapter One: The Heroines Knock at the Same Time

The heroines knocking at the same time was harder to write into the club log than the death notice.

Kagami Hana had brought barley tea. Shirayuki had brought a first-aid kit. They looked at each other's bags, then at Yoruichi, and suddenly laughed together.

"The Observation Club is going to be dissolved," Kagami Hana said. "A hub cannot stay open to people for long."

"Then leave both monitors," Shirayuki said, setting the first-aid kit down. "We observe the world. We do not observe who is supposed to stay."

Chapter Two: Notice of the Observation Club's Dissolution

The dissolution notice was printed very formally, stamped with the school's seal. Yoruichi folded it into a paper plane and sent it out the clubroom window. In the wind of two worldlines the plane split into two, then stacked back into one over the schoolyard.

"That counts as a success," Kagami Hana judged.

The light of the monitors slowly weakened, as if someone had pulled the hub's plug halfway out and could not bear to pull out the other half.

Final Chapter: Still Glowing After School

After school the clubroom was still glowing, only the light came from the sunset, not the screens.

The three of them stacked the chairs. On the door Yoruichi stuck a note: Observation over. Ordinary days begin.

The rooftop railing was still there. He did not go near it. The key was later fished out of the drain, rusted into a very handsome failure.

They made it into the clubroom's keychain. It opened no door at all, but it could open the hours after school.