Mallory quickly reversed the engines. For a moment nothing seemed to be happening and then quite suddenly Fleur de Lys slid backwards.

“That settles that,” he said. “We obviously aren’t going to get any further.”

He cut the engines, went out on deck and climbed on top of the wheelhouse. The reeds were very thick at this point, but to the left was a small lagoon, circular in shape and perhaps a hundred feet in diameter.

He pointed to it as Guyon scrambled up beside him. “Our one chance.”

He jumped to the deck, went into the wheelhouse and started the engines. As they rumbled into life he spun the wheel and crashed the boat into the reeds as she gathered speed.

For a moment they seemed an impenetrable barrier and then they slowly parted and Fleur de Lys passed through into the lagoon. Mallory cut the engines and she moved slowly to the far end and came to a halt, her prow grounding gently against a sandbank.

“No time to waste,” he said. “One of us stays with the boat. The other goes for Granville and his wife.”

“That had better be me,” Guyon said. “We have mutual acquaintances. I think he would trust me.”

Mallory pulled the chart forward. “You’ll do better by going on foot and swimming the intervening channels.” He opened a drawer and produced a pocket compass. “Keep due west and you can’t miss the central island. About a quarter of a mile away.”

“Getting Granville back here might be difficult,” Guyon said. “He’s an old man.”

“But used to these marshes. That’s why he comes here, remember. You’ll have to make out the best way you can.” Mallory produced the revolver he had taken from the young sailor at the castle and held it out. “Not much, but better than nothing.”

Guyon pushed it into the pocket of his oilskin jacket and went out on deck quickly. He jumped from the prow to the sandbank and plunged into the reeds.

Mallory lit a cigarette and stood on deck in the quiet rain. Perhaps five minutes later he heard the sound of an outboard motor passing along the main channel. It moved into the distance, muffled by the fog, and then there was only silence.

As Guyon went through the reeds a curlew whistled hauntingly somewhere to the left and wildfowl called as they lifted from the water, disturbed by his passing. He came out on higher ground, checked the compass and ran forward, alone in a land of shining mudflats, lonely creeks and everywhere the reeds.

He came to the end of solid ground and waded across a narrow creek, his feet sinking into soft mud. He could taste the salt on his lips and it stung his eyes painfully, but he kept on moving, pushing through the reeds into the grey shroud.

Gradually the ground became firmer again until he was able to run across sand and coarse marsh-grass. A few moments later he stood on the banks of a shallow lake and the house loomed out of the fog on its island fifty yards away.

The evil, scum-covered waters reached out to meet him as he moved forward, and he took out the revolver and held it above his head. It was not likely that the water would affect it, but there was no point in taking chances.

It was surprisingly easy going, the mud giving way to hard sand, and he was soon moving up on to dry land again. As he ran towards the single-storeyed house a narrow wooden jetty loomed out of the fog and he paused abruptly. No boat was moored there, not even a marsh punt. He stood there, a frown on his face, considering the fact, then turned and went towards the house.

He could smell wood smoke and saw it lifting in a blue tracer from the rough stone chimney. He went up rickety wooden steps to the porch, opened the door and went in.

The room was furnished simply but comfortably, loose 160 rugs scattered across the polished wooden floor. There were several bookcases, all filled, a sofa and two easy chairs in front of the fireplace.

Logs smouldered fitfully on the stone hearth, heavily banked with ashes that they might not burn too quickly. They told Guyon all he needed to know. Henri Granville and his wife were not there. But, then, they should have always counted on that as a possibility.

Ornithology was the old man’s great hobby. He had even written a book on the subject. It was quite obvious that at this moment he and his wife were sitting in their boat somewhere among the reeds which covered so many square miles of the marshes, probably even in some bird-hide since dawn taking photos.

He moved outside and went down to the jetty. Faintly, through the mist, came the sound of an outboard motor. Jacaud and his men. For them the solution would be obvious. They would simply wait for Granville to put in an appearance. No need even to go looking for him.

There was only one answer to the problem and Guyon waded into the lake and pushed towards the other side. He moved up on to high ground and ran along the shore towards the sound of the motor.

In spite of the clammy cold of the marshes sweat trickled from Feelings armpits. Ever since that first moment of shock when Fleur de Lys had passed them in the mouth of the estuary he had felt sick and frightened. And then de Beaumont’s message over the radio, the mind numbing as the operator decoded it.

The message was quite plain. Under the circumstances they were to return at once. But that hadn’t been good enough for Jacaud. He had insisted on going on into the marsh and Fenelon had wilted under his cold fury.

The reeds lifted like pale ghosts on either hand, the only sound the steady rattle of the outboard motor. He sat in the stern at the tiller, two sailors in the centre with rifles. Jacaud sat on the edge of the rounded prow, his sub-machine-gun slung around his neck as he gazed into the fog like some great bird of prey.

He turned, his granite, brutal face running with moisture. “We must be almost there. Cut the motor. We’ll start paddling.”

“You’re wasting your time, Jacaud,” Guyon called gaily. “I beat you to it. By now Henri Granville and his wife are well on their way out of here.”

As the dinghy drifted forward, a sandbank reached out from the reeds like a pointing finger. Guyon stood on a small hillock at the far end. His hand swung up and he fired twice. One of the sailors groaned and went over the side, still clutching his rifle.

Jacaud slipped the sub-machine-gun over his head. It came up in a long, stuttering burst of fire, slicing through the reeds. He was too late. Guyon had disappeared like a ghost into the fog. He laughed mockingly somewhere near at hand and then there was silence.

The remaining sailor leaned over the side to pull in his comrade. Jacaud turned and struck up his arm. “Leave him. We haven’t time.”

The sailor recoiled from the killing fury, the devil’s face that confronted him. The curious thing was that when Jacaud spoke his voice was quite calm.

“Back to L'Alouette and give that motor everything it’s got. Mallory’s got to return to lie de Roc. He’s no choice. His girl-friend’s still there. If we’re lucky we can catch them on their way out to sea.”

To Mallory the rattle of gunfire in the distance was like a physical blow and he walked the deck in impotent fury, hoping desperately that whatever had gone wrong Guyon had been able to handle it. Perhaps ten minutes later he heard the sound of the outboard motor returning along the creek. He stood very still, one foot on the rail, listening as it passed downstream.

He clambered on top of the wheelhouse and looked towards the west, straining into the fog. It was a good fifteen minutes before he heard the sound of brent geese calling bitterly as they lifted from the reeds. As the beating of their wings subsided, he was aware of movement towards the left.

He took a chance, cupped his hands and called: “Raoul! Over here!”

A couple of minutes later Guyon emerged from the fog and stumbled across the sandbank. Mallory ran to the prow and hauled him on board. Guyon was soaked to the skin and bitterly cold, his face pale and drawn.