Looking back I think that I myself was possessed by a devil which knew exactly what it was about. Blood sacrifice and fireworks are unnecessary when there is an eager human spirit ready to give a temporary home. To break him at any cost was what I wanted, to have him gibbering the truth of the gold and his reason for murder.

The dinghy was nearer in than I thought, riding just off a peninsula of the terrace. Marrin had anchored none too soon. I swam along the angle between rock and mud like a Severn lamprey seeking blood to suck until with two good kicks I could reach the mooring. The mysterious jerk on the rope produced some startled movement on board which then quietened down.

With hands and knees grasping the stem and out of sight, I put head and shoulders over the bows dressed exactly as I was when he tried to kill me and remained perfectly still. He was standing in the stern looking for the inlet. When he turned round and saw me, he stared, frozen. Then he tried to fend off this motionless phantom with movements of the arms as if he were swimming or clearing a mist of smoke before the eyes. Not surprisingly the dinghy tipped – if I helped it at all it was accidental – and he went overboard with a coughing yell, crashing his head on the outcrop of rock, just underwater, which had allowed my approach. The ebb caught him and swept him away from the boat, and he was on his way down-channel with any carcases and timber which the Severn had gathered to itself since morning.

I heard no more of him and saw nothing. I should have expected Marrin, considering his intimacy with spirits, at least to try to talk to my uneasy ghost instead of panicking. I hoped he would be swept ashore on the sands of the Noose. God knows I did not want him dead, for you cannot interrogate the dead.

My first intention was to swim ashore below Hock Cliff regardless of the difficulty of ever regaining the opposite bank till daylight, and to leave the dinghy as it was and at anchor; but the speed with which Marrin had been swept away was terrifying and only my hand on the gunwale prevented me from following. So I climbed on board, shipping a good deal of water, and started the engine which would not hold us against the tide but allowed me to ease the boat into the shore of the Noose not too far down. Then I gave it a shove and sent it spinning on its way to the sea. I wished there to be no awkward mystery about Marrin’s death. More charitably, I hoped the dinghy might be of use to him if both were stuck on the same sandbank.

I now had to return to Bullo and recover my clothes. It was a long and wearisome plod over the Severn’s special mixture of mud and sand until I reached the seawall of the Awre peninsula. I was not as cold as on the night of my escape, but it was essential not to be seen. Fortunately it was near midnight in a world emptied of men and I disturbed nothing but sheep while walking along the river to the copse and my baby pill. When I had changed I did not take the lane under the embankment, which was much too close to the cottages, but climbed directly up and over the railway. There, carrying my bundle, I must have been seen against the skyline by some gardener or fisherman trying to forecast the next day’s weather by inspecting the sky instead of going to bed.

After I had crossed the main road, the journey was easy enough: up a farm track and then a footpath with only a mile to go before I was safely under the oaks in one of the thickest parts of the Forest. There I became hopelessly confused, for there were rides and tracks in all directions and few visible stars to help. I should have been out till dawn if I had not crossed my usual path to Broom Lodge at a spot where I could recognise it.

I entered my den at first light, dead tired and unable to start out again if I had wished. I ate whatever was handy and turned in. News of the major’s burglary could wait. It seemed likely to fail and was futile. Even if the cauldron were proved to be of great antiquity I had no longer any hope of finding the barbaric hoard from which it had come.

In the late afternoon I set out for an evening visit to the sapling stump, keeping up my usual precautions since the hasty gulpings of the Severn might have rejected Marrin as indigestible and thrown him up on shore. I did not expect any message at all from the major. The pessimism of melancholy inclined me to believe that by this time he would have been handed over to the police or – if the commune wished to keep the scandal in the family – be locked up in disgrace pending Marrin’s return.

Half an hour after I was settled in cover a very thoughtful Denzil appeared. He had evidently made several visits in the hope of finding me.

‘At last! At last!’ he exclaimed.

‘Did you pull it off?’

‘Yes, yes!’ – success no longer seemed to interest him – ‘Simeon has disappeared. I hope … I hope … What did you see?’

‘I saw him leave Bullo Pill in his dinghy and go down on the ebb. That was all. Hasn’t he come back?’

I was keeping the full story to myself. The major knew too much already and was naturally apprehensive.

‘Not like him! Never missed a day!’

‘He might be stranded on the opposite bank,’ I suggested tentatively.

‘Would have telephoned. You’re sure you … well, I mean he was all right when you left him?’

‘I didn’t leave him. I watched him arrive and after that all I saw was the wake of the dinghy when he started out. So you got the cauldron?’

‘I could have. No trouble. No trouble at all.’

‘But you didn’t take it?’

‘Got in all right, made a mess of the place. Turned out the drawers and stole a few trinkets. But I hadn’t got the key of the casket. I think Simeon keeps it on him.’

‘You could have taken the whole thing.’

‘Too heavy, Piers. Couldn’t go down the drain pipe with that. I’d have had to throw it out of the window. Crash! Wake somebody.’

‘Why the hell didn’t you break it open?’

‘Hadn’t the heart. All that ivory work. And the bowl? What is it? We don’t know, do we? Could be … could be sacrilege.’

It wasn’t difficult to guess the cause of the inhibition. The major had no hesitation in burgling the sanctum of alchemy, which he knew to be partly play-acting, but when it came to violating the golden bowl his illusions, reaching all the way back to the Dark Ages and Arthur, Champion of Christendom, prevented possible sacrilege.

‘Don’t tell me you think that crazy murderer is the Guardian of the Grail?’

‘What makes you say that?’

My remark, more a spark of exasperation than serious, had struck home. I could have disclosed that I had witnessed the pagan ceremony which was far from a proper use of the Christian Grail, but I didn’t. The swings and roundabouts of his own heretical funfair were much too unpredictable.

‘Because I don’t see Marrin as Perceval. The thing was probably the favourite drinking bowl of some Saxon or Dane, or older still and the property of Nodens. Blood from his enemy or wine from his vineyard, depending on how civilised he was.’

‘You believe he existed before he became a god?’

‘Marrin does. And you said yourself that there is always a truth behind legend.’

All side issues of no immediate importance. I asked him if anyone had been in the laboratory since the burglary.

‘Unlikely. I locked it all up again.’

‘And the broken window – has nobody noticed it?’

‘I don’t think so. Too high up. Eyes down. Meditation. Work.’

Wearily I demanded what he had done with the swag. He marched off into the open order of the trees, beckoning me to follow as if any speech were an indiscretion. At first he could not find the right oak, though it was the only one which had a low branch close to the ground. He climbed from that into a much higher fork – he must, as he said, have been good at P.T. – and recovered a small bag well hidden by a bunch of mistletoe.