The souls saw them coming and made up their minds. The big one darted for the staircase and the others went streaming after, up alongside the crisp green line painted on the wall. Master Spiderman hopped on one foot in order to stop, spun round and went hammering up the stairs behind them. So, perforce, did Cat and Tonino.

As they all got to the top, another nun was just coming through a swing door, holding it open with her back so that she could wrestle a big tray with bottles on it through the door too. The souls swirled neatly around her huge starched headdress and on into the ward beyond. The nun did not see them. But she saw Master Spiderman with his face stretched into a grin of effort bounding towards the door like a maniac monkey, and the two dirty, perspiring, cobwebby boys behind him. She dropped the tray and screamed.

Master Spiderman barged her aside and dashed into the ward, dragging the boys with him.

They were in a long, dimly lighted space with a row of beds on either side. The souls were about halfway down the room, flitting cautiously in their usual cluster. But the place was not quiet. Cat had the strange feeling that they had just burst into a rookery. The air rang with peculiar cawing noises.

It took him a second or so to realise that the cawing was coming from little white cradles that were hooked to the bottom of each bed. All the people in the beds were ladies, all looking rather exhausted, and in each cradle there was a tiny, wrinkly, red-faced new born baby – at least, there were two of them in the cradle nearest Cat – and it was the babies who were making the noise, more and more of them, as the nun’s scream and the crash of the bottles, followed by the thunder of the door and the shout of anger Master Spiderman gave as he towed Cat and Tonino between the beds, woke every single baby there up.

“We’re in a maternity ward,” Cat said, wishing he could back straight out of here again.

Tonino was horribly out of breath, but he managed to grin. “I know. The souls are being clever after all.”

Master Spiderman was shouting, “Stop them! Don’t let them get into any babies! They’ll be gone for good then!” He dived at the cluster of souls with his butterfly net raised.

The souls did seem to be showing intelligence at last. As Master Spiderman dived, they rose up in a group above his waving net and then peeled apart in eight different directions. For a second or so, Master Spiderman did manage to keep most of them up in the air by swatting at them and shouting, but then two dived over behind him.

Like a pair of shooting stars, the ivy leaf and the fig leaf shot downward to two of the cradles. Each poised for a moment over a yelling baby and then softly descended into the baby’s wide-open bawling mouth. And were gone. A look of acute surprise crossed the face of each baby. Then they were yelling louder than ever with their faces screwed up and their short arms batting the air. It must feel very strange, Cat thought, suddenly to find you had two souls, but he could not see that it did any harm. And it was the perfect place to hide from Master Spiderman.