They were unarmed. Larry cursed the fact, but Tina had no way of getting a weapon without causing official comment. Larry started for the window where the city stretched, more active now, under the red and gold glow of a setting sun. Lights were winking on; the dusk of twilight was at hand. "Come now," said Tina, "before Tugh returns." "Where is Harl's room?" "Down under the palace in the sub-cellar. The corridors are deserted at this hour, and no one will see us." * * * * * They left Larry's room and traversed a dim corridor on whose padded floor their footsteps were soundless. Through distant arcades, voices sounded; there was music in several of the rooms; it struck Larry that this was a place of diversion for humans with no work to do. Tina avoided the occupied rooms. Domestic Robots were occasionally distantly visible, but Tina and Larry encountered none. They descended a spiral stairway and passed down a corridor from the main building to a cross wing. Through a window Larry saw that they were at the ground level. The garden was outside; there was a glimpse of the Time-cage standing there. Another stairway, then another, they descended beneath the ground. The corridor down here seemed more like a tunnel. There was a cave-like open space, with several tunnels leading from it in different directions. This once had been part of the sub-cellar of the gigantic New York City--these tunnels ramifying into underground chambers, most of which had now fallen into disuse. But few had been preserved through the centuries, and they now were the caverns of the Robots. Tina indicated a tunnel extending eastward, a passage leading to a room beneath the Robot laboratory. Tugh and Tina had used it that morning. Gazing down its blue-lit length Larry saw, fifty feet or so away, that there was a metal-grid barrier which must be part of the electrical fortifications of the palace. A human guard was sitting there at a tiny gate-way, a hood-light above him, illumining his black and white garbed figure. Tina called softly. "All well, Alent? Tugh has not passed back?" "No, Princess," he answered, standing erect. The voices echoed through the confined space with a muffled blur. "Let no one pass but humans, Alent." "That is my order," he said. He had not noticed Larry, whom Tina had pushed into a shadow against the wall. The Princess waved at the guard and turned away, whispering to Larry: "Come!" There were rooms opening off this corridor--decrepit dungeons, most of them seemed to Larry. He had tried to keep his sense of direction, and figured they were now under the palace garden. Tina stopped abruptly. There were no lights here, only the glow from one at a distance. To Larry it was an eery business. "What is it?" he whispered. "Wait! I thought I heard something." In the dead, heavy silence Larry found that there was much to hear.