By the third hour in the reeds, everyone had decided the Koibra was a coward. The clerk could feel the thought moving through the skiff, though the guide and boatman would not have approved. It passed from the younger apprentice to the poleman standing ankle-deep at the bow. It settled over them like gnats. The Koibra had left signs all morning, but never itself.

There were drag marks in the mud where something heavy had crossed from one channel to another. There were feathers floating in a bend where waterfowl had taken off too late. Once, the guide found a shed scale caught against a blackroot stump and held it up between two fingers. It was longer than a hand, slick as old oil, and banded faintly beneath the surface, as though the color had been laid under glass.

The guide wrapped the scale in oiled cloth and gave it to the clerk. “Near the boundary,” they said.

The clerk wrote that down. They had written many things down already: reed breakage, bird absence, mud displacement, depth uncertain. The wax on the satchel had been scraped by briars and smeared with marsh grit. By now the whole party looked less like a civic survey and more like a group of people the fen had chewed for taste and chosen not to swallow.

The Lowfens lay ahead, though “ahead” meant little in a place where water bent around itself and every clear passage liked to change its mind. The Highfens had reed walls and hidden channels, but they still belonged to maps, if the mapmaker was patient and honest. The Lowfens did not. They spread low and green and silver beneath the afternoon haze, fertile and treacherous, a country of floating ground and patient mouths.

Of course, traders wanted to know whether the Koibra had pushed south. Barge masters wanted to know which channels to avoid. Their sponsor in the League wanted warning markers raised before a missing skiff became a missing convoy. The League loved nothing so much as learning from danger one death too late.

The younger apprentice had been the first to say that last part, which made the clerk snort hard enough to smudge a line. Now the younger apprentice watched every reed as if it owed them an answer.

“You’ll wear holes in the grass,” the poleman said.

The apprentice tried to laugh and did not quite manage it. “Good. Then I’ll see what’s hiding behind it.”

“More grass,” the clerk said.

That got a laugh. Even the guide allowed a small breath through the nose, which was as close as they had come to amusement since sunrise. The apprentice’s shoulders dropped a little, and for a while the skiff moved on with only the sound of water sucking at the pole and insects stitching the air.

The trail ended at a shallow mirror of black water crossed by mats of yellow-green weed. Beyond it, the land changed, subtly. The air felt different, thicker and lower, as if the sky had leaned down to listen.

The guide raised one hand.

The poleman stopped.

For a moment, everyone obeyed the silence. Then something moved at the edge of the mirror.

It rose from the water in a long, dark curve, slick with mud and trailing weed. It turned as the current took it, showing a pale underside. In the poor light it looked like a head lifting. It looked like a coil. It looked like every story ever told in a dockside room by someone who had not been there but knew someone who had.

The younger apprentice made a sound like a dog kicked by surprise. They lurched back so hard the skiff tilted. One hand slapped the clerk’s shoulder, the other flung their reed pole away as if it had become a Koibra itself. Mud took them to the knee before the poleman caught their collar and hauled them upright.

The thing bumped harmlessly against a weed mat. For half a breath, no one moved.

Then the current rolled it over, and the monster became a root.

The clerk’s laugh came out too loud, sudden and ragged, and that made the poleman laugh too. The older boatman looked away, but his beard shook. Even the apprentice laughed once they had both feet under them, red-faced and dripping, though their laugh sounded like it had been pulled through a reed pipe.

“Careful,” the clerk said. “That root nearly filed a complaint.”

The poleman slapped the side of the skiff. “No, no, it was worse than that. Did you see its teeth?”

“It was looking at me,” the apprentice said, trying to save an ounce of face.

That made it worse. The laugh went around again, tired and grateful and a little wild. The apprentice bowed to the floating root with one muddy hand pressed over their heart, and everyone laughed harder.

The laugh was still moving through them when the reeds behind the root burst open.

The Koibra came out running, all banded muscle, black water, and a head low enough to vanish between one stride and the next. The skiff happened to be in front of it. That was all. That was enough.

The apprentice made the same sound again.

No one laughed.

The Koibra struck the mud-flat hard enough to throw water into the skiff. Its body flexed in terrible sections, smooth and fast and wrong for something so large. The poleman shouted. The older boatman seized the stern rope. The guide reached for the apprentice, but there was nowhere to move that was not water.

Then the water in front of the Koibra swelled.

At first it seemed the fen itself had drawn breath. A length of peat-shadow lifted from the channel floor, shedding weed and silt. Then the shape became a head, broad and flat and mud-slick, with eyes set far apart and pale feelers dragging from its jaw. It was fish and frog and something older than either, its mottled throat ballooning once beneath a mouth wide enough to take the Koibra crosswise.

The Koibra tried to turn.

The Marshmaw swelled to meet it, blunt forelimbs biting into the mud.

There was no roar. Only water collapsing, reeds snapping flat, and the wet, heavy sound of a body being made smaller than the thing that held it. The Koibra’s tail lashed once across the surface. Mud struck the side of the skiff. Then the Marshmaw sank, taking the thrashing shape with it, and the channel closed over them both as if embarrassed by the interruption.

No one joked after that.

They made camp on the firmest ground the guide would allow, which was still soft enough that bedrolls took the shape of old footprints. The clerk tried to write by lantern and found the page had gone damp at the corners. The poleman checked the skiff ropes three times. The older boatman boiled bitter tea and said nothing while people accepted cups with both hands.

The younger apprentice laughed once during supper, before anyone else could.

“Root almost had me,” they said. The words sat between the cups and the gnats.

The poleman smiled because he was kind. The clerk smiled because they did not know what else to do. No one added to the joke, and after a while the apprentice stopped trying.

Later, when the others had settled into the uneasy sleep of people pretending they trusted the ground, the clerk found them at the waterline.

The apprentice sat on a hummock with their knees drawn up, holding the thrown pole across their lap. They were cleaning it with a strip of cloth. The pole was already clean. Each pass of the cloth made the reed shine a little in the lantern light, then dull again as mist settled over it.

The clerk remembered their own voice, bright and stupid over the water. Another joke almost escaped. The words would have come easily. They waited at the clerk’s teeth, ready to make the night smaller. Ready to make the fear belong to morning.

Then the apprentice looked up.

Their face was calm in the way a tied rope was calm. All the strain had gone into holding still.

“I know,” they said. “It was a root.”

The clerk sat beside them. The hummock dipped under the added weight, and black water breathed quietly around its edges. Neither of them spoke for a while. Across the marsh, something clicked inside the reeds, then clicked again farther away.

“I laughed because I wanted it to be a root,” the clerk said.

The apprentice looked down at the pole. Their fingers tightened once and loosened. “It was.”

“The first thing was.” The clerk rested their elbows on their knees and watched the mist gather over the boundary. “Then the Koibra ran.”

The apprentice swallowed.

“You saw something before the rest of us knew there was anything to see.”

“That is a generous way to describe falling in the mud.”

“I am not being generous.”

That almost earned a smile. It moved across the apprentice’s mouth and failed, but not entirely.

The clerk reached for the spare cup they had brought and passed it over. The tea had gone lukewarm, which made it easier to drink but worse in every other way. The apprentice took it anyway. Their hands shook once around the cup, then steadied when the clerk pretended not to notice.

“I thought I was being stupid again,” they said.

“So did I.”

The apprentice looked at them then.

The clerk kept their eyes on the water. “That was the part I got wrong.”

The marsh made its small night sounds around them, though it no longer sounded like laughter waiting to happen.

“Do we go back that way tomorrow?” the apprentice asked.

The clerk looked toward the water. The Lowfens lay beyond the dark, unseen but present, keeping their own counsel. Somewhere in the reeds, the place where the Koibra had vanished would look like any other channel by dawn. Somewhere deeper, the Marshmaw moved through waters no marker would ever hold.

“Yes,” the clerk said. “But not alone.”

The apprentice breathed out, making a sound that was not relief, not fully.

In the morning, they returned to the skiff.

The poleman made no joke when the apprentice stepped in slowly. The guide only watched the water and gave one small nod when the apprentice picked up their pole. The clerk took the place beside them, close enough that their shoulders touched when the skiff rocked.

At the edge of the mirror, the apprentice paused.

A reed bent.

This time, they set the pole into the black water, felt for the bottom, and waited until the clerk set theirs beside it. Together, they pushed away from shore.