You sit on the boards like a person who has decided not to be a legend tonight.

The notebook’s first page gets a heading: Hollow Marsh lights. Time. Wind. What they do. You mark three pale coins on the water. When the breeze shoves from the west, the coins shove too. When the breeze rests, they rest—or they slide along a darker ribbon that might be a channel.

Jonah crouches, flashlight under his chin for drama, then thinks better of it. “If we don’t chase them, how do we prove they’re wisps?”

“We prove what they are,” you say. “Wisps is a name. Names aren’t evidence.”

He huffs, but he watches. One light is only a star caught in a puddle; when a cloud covers the star, that one dies. Another keeps a faint blue, even under cloud—maybe a tiny flame over bubbling peat, the kind old stories called will-o’-the-wisp and blamed for stolen travelers. The travelers, you guess, stole themselves by leaving the path.

Jonah wants to run. You want to watch-don’t-follow, which is a duller sentence and a smarter night.

Ms. Ellison’s cottage sits inland, a square of yellow window. She keeps the marsh scrapbook. The stump at the bend of the boardwalk is doing something else entirely: a low green hush, not a wandering coin.