Patrick stood there eyeing the swan, just hoping that sooner rather than later the swan would decide it was time to go back into the water. But the swan stayed steadfastly where he was, glaring darkly at him, his great black feet planted firmly on the towpath. He was showing no signs of moving anywhere.

Patrick was still wondering what to do, when out of the corner of his eye he saw something floating out in the middle of the canal. It was bright green and looked plastic – a sack of some kind. He probably wouldn’t have paid it any more attention – a sack’s not that interesting, after all – if he hadn’t heard the squeaking. It sounded as if it was coming from the sack itself, and that didn’t make sense.

Patrick thought at first it might have been the piping of ducklings or moorhen chicks – he’d heard them often enough on the canal. But then he remembered that there weren’t any chicks around, not any more, because it was autumn. The whole place was carpeted with yellow leaves, gold leaves, red leaves. They were all around his feet. Spring and summer were over. No, it really had to be the sack itself that was squeaking.

It was still early in the morning and Patrick’s brain must have been working very slowly, because several moments passed before he realised that there was something alive inside the sack, and even then it wasn’t only the squeaking that convinced him. The sack, he noticed, wasn’t just drifting gently along like everything else, the leaves, the sticks, all the other flotsam in the canal. It was turning of its own accord, as if it was being propelled from the inside. There was definitely something inside it, and whatever it was seemed to be struggling against the side of the plastic sack, kicking at it, trying to escape from it and squeaking and squealing in terror. He had no idea what it might be, only that it was alive and in danger of drowning. The canal wasn’t that wide. It was dirty but it wasn’t wide. He could do it.

Patrick didn’t think about it any more. He shrugged off his school bag and leaped into the canal. He knew he was a good enough swimmer, so he wasn’t worried about drowning, only about getting cold and wet. He didn’t want the canal water in his mouth either, so he kept it tight shut. Just a few quick strokes out into the canal and he’d grabbed the sack, turned, and was swimming back again. Suddenly the bank seemed a long way away, but he got there.

Climbing out was the most difficult part because his clothes were heavy and clinging, and the sack was slippery in his hands, difficult to hold on to. He felt suddenly very weak, felt the cold of the water chilling him to the bone. But with one huge effort he heaved himself up, enough to hook one leg up, on to the bank, and then he was out. Standing there, dripping from everywhere, he untied the sack and opened it. There were five puppies inside, leggy, gangly looking creatures, skeletal almost, all of them trembling with cold and crawling over one another, squirming to get out, mouths open and squeaking frantically. They were like no puppies Patrick had ever seen before.