There was an ongoing argument about the shape of the xenocs. They were undoubtedly shorter than humans, and they probably had legs, because there were spiral stairwells, although the steps were very broad, difficult for bipeds. Lounges had long tables with large rounded stool-chairs inset with four deep ridges.

After the first fifteen minutes it was clear that all loose equipment had been removed. Lockers, with the standard dilating door, were empty. Every compartment had its fitted furnishings and nothing more. Some were completely bare.

On the second deck there were no large compartments, only long corridors lined with grey circles along the centre of the walls. Antonio used a dimple at the side of one, and it dilated to reveal a spherical cell three metres wide. Its walls were translucent, with short lines of colour slithering round behind them like photonic fish.

«Beds?» Schutz suggested. «There's an awful lot of them.»

Marcus shrugged. «Could be.» He moved on, eager to get down to the next deck. Then he slowed, switching his collar focus. Three of the hemispherical blisters were following him, two gliding along the wall, one on the floor. They stopped when he did. He walked over to the closest, and waved his sensor block over it. «There's a lot of electronic activity inside it,» he reported.

The others gathered round.

«Are they extruded by the wall, or are they a separate device?» Schutz asked.

Marcus switched on the block's resonance scan. «I'm not sure, I can't find any break in the composite round its base, not even a hairline fracture; but with their materials technology that doesn't mean much.»

«Five more approaching,» Jorge datavised. The blisters were approaching from ahead, three of them on the walls, two on the floor. They stopped just short of the group.

«Something knows we're here,» Antonio datavised.

Marcus retrieved the CAB xenoc interface communication protocol from a neural nanonics memory cell. He'd stored it decades ago, all qualified starship crew were obliged to carry it along with a million and one other bureaucratic lunacies. His communication block transmitted the protocol using a multi-spectrum sweep. If the blister could sense them, it had to have some kind of electromagnetic reception facility. The communication block switched to laserlight, then a magnetic pulse.

«Nothing,» Marcus datavised.

«Maybe the central computer needs time to interpret the protocol,» Schutz datavised.

«A desktop block should be able to work that out.»

«Perhaps the computer hasn't got anything to say to us.»

«Then why send the blisters after us?»

«They could be autonomous, whatever they are.»

Marcus ran his sensor block over the blister again, but there was no change to its electronic pattern. He straightened up, wincing at the creak of complaint his spine made at the heavy gravity. «OK, our hour is almost up anyway. We'll get back to Lady Mac and decide what stage two is going to be.»

The blisters followed them all the way back to the stairwell they'd used. As soon as they started walking down the broad central hallway of the upper deck, more blisters started sliding in from compartments and other halls to stalk them.