The red glow of the lantern didn't do much for footing, except to make the filth they waded through more visible. Fukuda's sleek chakra was a roil of disorder; she couldn't chakra-walk reliably, and so Ryouma sloshed beside her, with her hand curled like a cuff above his elbow. The stench of rot mingled with sewer-reek and curdled in his throat.

They found the grate, and stumbled over it; Fukuda nearly put her foot through one of the gaps. She was sweating, breathing open-mouthed. So was he. It helped with the stench, a little.

Another pipe opened into the main tunnel, on the other side of the grate; the current tugged at their knees now, instead of their calves. Each step splashed up to Ryouma's thighs. He couldn't hear Genma coming behind him, or Raidou and Kakashi ahead.

"Think you can chakra-walk yet?" he asked Fukuda, glancing back. No lightstick glow catching up. Was Genma setting explosive tags, instead of risking being caught inside a jutsu's range? Genma's ANBU spark was the faintest ember, tamped down nearly to extinction. Kakashi and Raidou must be further away; he couldn't sense them at all.

Fukuda gritted her teeth. "Help me up."

Together, they clambered to the surface of the muck. Fukuda's chakra clenched, as her hand tightened on his arm. Her feet still dipped below the surface, then struck off with a sound like rubber. She lurched against him, swore, and tried again.

Slow going, but still better than wading. Ryouma stretched out his own chakra; after a moment, he dared pulse his ANBU spark.

Nothing pulsed back in response. But distantly, behind him, rocks splashed into water. Twenty seconds later, the sewer sludge rippled beneath their feet.

Ryouma looked back again. Fukuda tugged him savagely on.

"That's my lieutenant," Ryouma said, wrenching against her grip. "If he's—"

"He killed Niigaki Rikyu," Fukuda said, flatly. "He can take care of himself."

Maybe, but that didn't mean he should have to. And if something'd gone wrong— If there was another Kiri team in the sewers, following Rikyu's…

He pulsed his spark again.