Together they joined the mermen. There was no talk, nothing to break the splashing sound of bodies moving against the current. As they pressed on, Raf was sure that this was not the same way they had come. And once more Dalgard answered his unspoken question.
"We seek another door into the city, one long known to these tribesmen."
Raf would gladly have run, but he could not move faster than his guides, and while their pace seemed deliberate, they did not pause to rest. The whole city, he decided, must be honeycombed with these drains. After traversing a fourth tunnel, they climbed out of the flood onto a dry passage, which wormed along, almost turning on itself at times.
Side passages ran out from this corridor like rootlets from a parent root, and small parties of mermen broke from the regiment to follow certain ones, leaving without orders or farewells. At the fifth of these Dalgard touched Raf's arm and drew him aside.
"This is our way." Tensely the scout waited. If the stranger refused, then the one plan the scout had formed during the past half-hour would fail. He still held to the hope that Raf, with what Raf carried, could succeed in the only project which would mean, perhaps not his safety nor the safety of the tribe he now marched among, but the eventual safety of Astra itself, the safety of all the harmless people of the sea, the little creatures of the grass and the sky, of his own land at Homeport. He would have to force Raf into action if need be. He did not use the mind touch; he knew now the unspoken resentment which followed that. If it became necessary—Dalgard's hands balled into fists—he would strike down the stranger—take from him—Swiftly he turned his thoughts from that. It might be easy, now that he had established mental contact with this off-worlder, for the other to pick up a thought as vivid as that.
But luckily Raf obediently turned into the side passage with the six mermen who were to attack at this particular point. The way grew narrower until they crept on hands and knees between rough walls which were not of the same construction as the larger tunnels. The smaller mermen had no difficulty in getting through, but twice Raf's equipment belt caught on projections and he had to fight his way free.
They crawled one by one into a ventilation shaft much like the one he had climbed at the Center. Dalgard's whisper reached him.
"We are now in the building which houses their sky ship."
"I know that one," Raf returned almost eagerly, glad at last to be back so close to familiar territory. He climbed up the hand-and footholds the sea-monster lamp disclosed, wishing the mermen ahead would speed up.
The grille at the head of the shaft had been removed, and the invaders arose one by one into a dim and dusty place of motionless machinery, which, by all tangible evidence, had not been entered for some time. But the cautious manner in which the sea people strung out to approach the far door argued that the same might not be true beyond.