They were an efficient crew. It seemed less than an hour later that Berden and I were sitting in the captain’s cabin as the sailors rowed the ship out of the harbour into clear water and hoisted the sails. There was not much wind, so all three sails went up. I hoped that there would be no storm on the homeward journey, so there was only the cold to contend with. While on deck I had noticed that many of the ropes were sheathed in tubes of glassy ice that cracked and shattered as the sails were hoisted and the ropes ran through pulleys. As usual, most of the sailors went barefoot, for a better grip on deck or when they climbed the rigging. Their feet were blue with cold. Even in the cabin I was grateful for the small enclosed brazier that gave off a little heat. I held out my hands to it and the chilblains that had begun to develop during our ride from Amsterdam began to sting. Of course one should not expose chilblains to the heat of a fire, but the temptation was too great, until I was forced to draw my hands back and rub them. I cursed myself silently for my folly. The dog had left his straw bed and followed us into the cabin, so when the captain joined us, having set the ship on its course, I apologised for the dog.

‘No need to apologise,’ he said, ‘I like dogs and have two myself at home. How did you come by him, and why is he bandaged?’

I recounted a brief version of the dog’s history, saying only that his master was dead – not that he had been murdered – and that he had defended me when I was attacked.

The captain stroked the dog, running his ears through his fingers. ‘It seems he is worth keeping then. Ah, that reminds me.’ He got up and went to one of the cupboards set into the wall, which I saw was filled with papers and writing materials.

‘This came for you by messenger this morning from Amsterdam.’

I was surprised. Few people would have known that I would be taking ship here. It was a letter, merely inscribed ‘Dr Alvarez’, and closed by red wax which bore no imprint of a seal. Unconsciously I felt for the seal ring that I still wore around my neck but had had no occasion to use. Because of the blizzard and our trip to the south, there had been no opportunity to send word to Phelippes. I slid my thumbnail under the wax to lift it and unfolded the letter.

It was an unfamiliar hand. I looked down at the signature. ‘Hurst’.

The gentleman we both serve is in good health, thanks to the measures you recommended. He wishes me to convey his thanks and gratitude. The other person you know of has departed without leave, we know not where. The gentleman returns home shortly. I wish you a safe journey.

Hurst.

I beamed at Berden. ‘Hurst has been successful. And it seems the Earl no longer thinks me a fool.’ I decided to say no more for the present.

The captain was still on his feet, bringing out a flagon of his good wine and three heavy-bottomed glasses.

‘Good news, then?’

‘Aye, good news.’ I folded the letter up again and slipped it inside my doublet. I was surprised at the pleasure it gave me. I was vindicated, and my actions had almost certainly saved the Earl from poison. He might not have died, but his health had not looked good to me, so even prompt medical attention might not have saved him if he had taken the belladonna.

We moved to our seats round the captain’s table and he poured out the wine. ‘We should reach Dover sometime tomorrow, depending on the weather.’

‘Good,’ I said. ‘I have had enough of the Low Countries.’

They both laughed.

‘And what is the dog called?’ the captain asked.

In all this time the dog had remained nameless. The only person who might have known his name, the minister Dirck de Veen, had never mentioned it.

‘I will have to find him a name,’ I said. ‘I think it should be a Dutch name. Pieter?’

‘Jan?’ said Berden. ‘Lars?’

The dog ignored us.

‘I knew a captain called Rikki,’ said Thoms. ‘It’s usually a child’s nickname, but he was a big man, very brave.’

‘Rikki?’ I said. The dog looked up and thumped his tail. ‘He seems happy with that.’

‘It is short for Richard,’ said Thoms, ‘and that means “valiant”. From what you tell me, it is appropriate.’

I leaned down and caressed the dog’s head. ‘Rikki it shall be.’

Our return journey, compared with our outward one, was uneventful. Although it remained bitterly cold, there was no further snow but a steady following wind that carried us down the coast of the Low Countries until we came too near the Spanish-controlled ports and Thoms turned the ship toward England. The only concern was when we drew near the shifting shoals of the Goodwin Sands just as the early winter dark began to close down on the following day. In order to avoid any danger, Thoms steered the ship in a wide westward arc and the lookout perched at the top of the main mast sang out that he could see a Spanish ship in the distance, perhaps off Dunkerque. For a while there was an atmosphere of tension aboard, but by the time we had cleared the shoals the ship was lost to sight and we headed in toward Dover.

It was too late to start for London, so we would stay one night in the castle, relieved to be back on English soil and among friends. Before we left the ship, Captain Thoms had presented us each with a pot of his sister’s honey. In return, I drew out the two lemons I had carried with me all the way and never used, for I had sent back no despatches, secret or otherwise. Despite their rough journeys, the lemons were unharmed, and I gave them to Thoms.

‘Two lemons for you,’ I said, ‘against the scurvy.’

He smiled. ‘I am grateful to you, Doctor. And see, I have also laid in a supply of dried scurvy grass.’ He opened the cupboard where he kept his wine and showed me a bundle of the dried herb.

‘Excellent,’ I said. ‘That will serve your men well in the winter, steeped in hot ale. In the summer you will be able to buy fresh.’

We bade him and his men farewell and led the horses over the ramp on to Dover quay. Whether they knew they were back in England, I could not tell, but they seemed pleased to leave the ship. Rikki trotted at my heels, already beginning to look stronger after a few days of good food.

Up at the castle we left the horses and the dog in the stable and reported to Sir Anthony Torrington, who told us, rather ungraciously, that we could be accommodated for one night. He was one of those men who like to give the impression that they are busier than they really are, so spent his time moving papers about on his desk and barely glancing up at us. One of the soldiers showed us to a room, where we would be obliged to share with two others this time, but both were on night guard duty, so after exchanging a few words of greeting we did not see them again.

I saw nothing of Andrew until we joined the soldiers for a meal and then we had little time to talk, for he too was about to go on duty.

‘It was successful, your time in the Low Countries?’ he asked.

‘Successful, aye,’ I said. ‘And also eventful. I have come back with a dog and Berden with a knife injury, but we achieved what we were sent to do.’

‘Good. I may not see you again before you leave, but if I am in London, I will visit you at St Bartholomew’s.’

‘I did not think you would want to cross that threshold again,’ I said with a smile, ‘for it must hold bad memories.’

‘No, you are wrong. What I remember is being made well again.’

With that, he was off.

Before retiring for the night I called in at the stables and asked one of the grooms whether Rikki could stay with them until the morning.

‘I think he might not be welcomed in the soldiers’ quarters,’ I said.

‘He’ll do fine with us, Doctor. I fetched him a bone from the kitchen.’

Rikki looked up from the bone and scrambled to his feet, ready to follow me, but I shook my head and pointed down to the floor. ‘Wait there,’ I said. The dog could not be expected to understand the command or even my English words, but he seemed to understand the gesture. He returned to his bone and did not try to follow me when I left.