They forged on, chakra senses straining. Fukuda's breathing rasped harsh in Ryouma's ears; the muscles of her arm were rigid against him. The tunnel grew narrower, pressing them against each other. The ceiling scraped at Ryouma's head. He stooped, then stopped chakra-walking, dropping back knee-deep into the muck. Their pace slowed to a panting slog.

He tried to count paces, estimate distance. They'd covered half a kilometer from entering the sewer until hitting the grate. He started over again, estimating the gap widening between them and Kirigakure's walls: two kilometers. Three. Three and a half, and was that light ahead…?

Light and sound: a crash and roar of water, rising over even the sucking splash of their boots. Fukuda's pace quickened. They took the last hundred meters in a slipping, splashing rush, fast enough that Ryouma nearly missed the moment that rough-hewn rock tunnel transitioned to concrete culvert.

He couldn't miss the second grate, though. It lay half-submerged in sewer muck, blasted out of the culvert by a jutsu that had chewed huge chunks of concrete out of the culvert walls and left them scattered stumbling-blocks.

"No seals on this one," Genma panted. "And I didn't feel the chakra."

Which meant Kakashi was even farther ahead of them than Ryouma'd thought. Had he made it to safety already?

Ryouma stepped to the edge of the culvert, bracing himself with chakra and a hand on the weathered concrete rim, and looked out into the grey light of early dawn.

Below them, the stream of sewage choked a rocky bed. Thick foliage crowded greedily around its edges, luridly green even in this drained light, and spread out into a broad strip of cessfield. They helped filter the stream, but not by much; fifty meters away, a silvery river turned muddy at watersmeet.

Ryouma looked upstream, toward the waterfall. It tumbled in a misting ribbon from the shadowy shoulders of the mountains guarding Kirigakure's flanks. Froth churned at its foot, then broadened into a pool half-dammed by fallen boulders. The river ran swift and strong again below the boulders, sweeping up the effluent of Kirigakure's sewers and rushing out to sea.

Gemma said, pointing over Ryouma's shoulder: "There."

There was a scuffed patch on the virulently green streambank, where broken plants crushed into the mud. A man scrambling up the bank toward the river might leave that sort of mark, especially if he was moving fast and burdened…

Fukuda dropped from the culvert. She hit in a crouch and pitched to one knee. Ryouma and Genma leapt down after her, chakra-balancing on the surface of the stream, but Fukuda struggled to her feet before Ryouma could reach for her. She wrapped her arm around her ribs and staggered for the bank, for the torn ground where Kakashi or Raidou had left footprints and nothing else.

"They're not here," Ryouma said. "Lieutenant, they're—"

Genma's head lifted. The warmth of his chakra washed over Ryouma and through him, unfurling far beyond the limit of Ryouma's own stretched senses. His eyes unfocused, wide and blind.

Ryouma held his breath, and waited for Genma to find them.