The Wrong Trail

Fourteen-year-old Seren Mackay had not meant to get separated from the group. It had happened in the way that most genuinely inconvenient things happen: gradually, and then all at once. One moment she had been walking at the back of the line of twelve students moving along the forest trail in Costa Rica, listening to their guide, Eduardo, explain the difference between two types of bromeliad, and the next she had stopped to photograph a blue morpho butterfly that had landed on a leaf at eye level, and when she looked up the group had rounded a bend and disappeared and the cloud forest had closed around her in its thick, dripping, green and silent way.

She stood still for a moment and listened.

The forest made an enormous amount of noise for somewhere that felt so quiet. There was water everywhere: dripping from the canopy, running in thin streams over the mossy rocks, condensing on every leaf and pooling in the cups of the bromeliads. There were birds, high up and invisible, and insects, and somewhere below her on the slope, the sound of a larger stream. What there was not was the sound of twelve students and a guide.

Seren was on a school trip, ten days in Costa Rica to study cloud forest ecology, which was her absolute favourite subject and the reason she had saved up for eight months to come. She was not, as a rule, a person who panicked. She was careful and observant and had a good memory for detail, and she had been paying attention to the trail on the way in, which meant she was reasonably confident she could retrace her steps to the trailhead if she needed to.

But she did not immediately retrace her steps, because something had caught her attention.

The butterfly had gone, but the leaf it had landed on was notable. Not for the leaf itself, which was an ordinary enough Heliconia, but for what was behind it. The vegetation at the side of the trail had been pushed aside here, recently, and behind it was a narrower path, barely visible, that ran at an angle to the main trail heading deeper into the forest and slightly downhill.

Seren looked at it for a moment. It was not a random animal track. The vegetation had been cut back deliberately in places, not with a machete, which would have left clean edges, but with something smaller, and the ground showed the impression of human footprints.

Someone used this path regularly. Recently.

Seren took a photograph of the main trail so she could orient herself later, marked the junction carefully in her mind, and went a few metres down the narrower path. Just to see. Just to see what was there.

She found the first marker after about twenty metres: a small cairn of three flat stones balanced beside the trail, exactly the kind of marker a person makes when they want to be able to find their way back. The stones were too deliberately placed to be accidental. Below the cairn, pressed into the mud, was the impression of a boot. Small, probably a child's.

The trail continued downhill. Seren checked her watch. She had perhaps an hour before the group would be back at the trailhead and would notice she was missing. She had her camera, a full water bottle, the small emergency kit the school had insisted everyone carry, and a compass.

She knew her general direction.

She went further down.

The cloud forest changed as she descended. The trees were different at this elevation, taller and more widely spaced, with enormous fern colonies at their bases and a canopy that let through more light. The mist was thicker here, the kind that reduced visibility to perhaps thirty metres and turned everything beyond that distance into grey-green shapes. She found two more cairns, spaced regularly, and then a section of trail where someone had tied small strips of orange plastic to the branches at intervals, the kind of flagging tape used by engineers and foresters to mark routes.

The flagging tape was relatively new. The plastic was still bright.

Seren was thinking about this when she nearly walked into the structure.

It appeared out of the mist like something from a dream: a small shelter, perhaps three metres square, built between four trees using their trunks as corner posts and roofed with a dense thatch of palm fronds that kept the interior dry. The walls were open on two sides, the other two screened with overlapping layers of large leaves, and inside it Seren could see a folding camp stool, a waterproof bag hung from a branch, a small weather station of the kind used to measure temperature and humidity and rainfall, and a notebook in a ziplock bag.

She stood at the edge of the shelter and looked at everything without touching it.

Someone had built this. Someone who knew the forest, who knew how to construct a shelter from local materials, who was monitoring the weather conditions here regularly and keeping notes. The weather station was solar-powered and appeared to be functioning, its small display showing numbers in the dim light.

Seren read the display. Temperature, humidity, and one more reading that made her frown. The display showed a counter, and the counter was showing a number she did not immediately understand. She photographed everything, including the display, and stepped back.

She needed to find the group. But she also needed to come back here, and to find out whose shelter this was, and why they were monitoring this particular section of forest.

She retraced her steps to the main trail, moving quickly but carefully, and arrived at the trailhead twelve minutes before the group did. She said nothing to anyone about the shelter.

But that evening, in the lodge dining room, she found herself sitting across from a girl she had not spoken to much yet, a local student named Valentina, who had joined the trip as a community liaison, a role that seemed to involve knowing everyone and everything. Valentina was fifteen, practical and quick, with the specific alertness of someone who grew up in a place they know extremely well.

Seren opened her camera and showed Valentina the photograph of the weather station's display.

Valentina looked at it for a long moment. Then she looked up at Seren with an expression that was equal parts cautious and curious.

"Where did you see this?" she said, quietly.

"In the forest. On a path below the main trail." Seren paused. "Do you know what that reading means?"

Valentina was quiet for a moment, looking at the photograph. Then she said, equally quietly, "I think you had better come with me tomorrow morning. Before the group goes out." She slid the camera back across the table. "And please don't show this to anyone else yet."

Seren looked at her steadily. "Why?"

"Because," said Valentina, "I think that shelter belongs to my uncle. And if it does, something has gone wrong."