Mercurius pulled his vizard closer around his face and ensured the cowl was full across his head. He sat by the window and looked out at the gathering dusk. The taverner had made a pathetic attempt at laying out a garden, a patch of sun-scorched weeds fenced off from the dusty, tawdry herb plots by sheepshank bones and the skulls of different animals. A slattern came over. Mercurius pulled out a silver piece.

‘Ale,’ he ordered. ‘Properly drawn and the blackjack had better be clean!’

He removed a small arbalest from the hook of his belt and placed it on the table. The slattern hurried off. Outside in the stable yard, two stallions jigged at the ostler and reared neighing, lashing out. Some of the customers went across to watch the fun. One rogue shouted that he was prepared to accept wagers that the ostler would be hurt. The taverner, a greasy barrel of a man, shoved them aside and walked out, a flaming brand in his hand, to separate the two stallions.

Mercurius eased himself in the corner. In the middle of the floor sprawled a member of a troupe of travelling actors, drunk as a sot. The man lay spread on his back, the devil’s mask still clasped to the top half of his face. A little boy crouched next to him wiping away the pool of spittle filling his slack mouth. Across the taproom other members fought for the takings. They hushed for a while as the flame man came down the street, ringing his bell and shouting at householders to be careful; fires were to be doused and candles made safe. Someone else bawled raucously that he had a fresh maid for sale.

The clamour in the stable yard now being stilled, the customers swirled back. Cunning men divided their takings, professional beggars, armed with wet rags, wiped off the paint and saltpetre which they used to display fictitious wounds. Mercurius waited, his eyes constantly moving, vigilant for any sheriff’s man or one of Gaunt’s spies. He did not know whether the English knew he was in London but he could take no chances. The business at Hawkmere was going well, yet he was not responsible.

He saw two shadows come to the door — his guests had arrived. They swaggered across, glimpsed the crossbow and recognised the sign. As they pulled across stools and sat down, Mercurius sipped from his tankard and studied them. Like two peas from the same rotten pod; they wore leggings and boots, their chests were naked except for leather jackets, the sleeves cut off, copper bands round their muscular arms. Their heads were completely shaven, their faces sharp and narrow-eyed. One of them fingered the copper ring in his ear lobe.

‘You are the one?’

‘I am.’

‘And what do you want?’

The assassin clicked his fingers and the slattern hurried across. Two more blackjacks of ale were ordered. One of the shaven-heads leaned forward, arms on the table.

‘We cannot sit here all night. What do you want? Our horses are outside. We can take what we want and go!’

‘If you talk to me like that again, I’ll kill both of you now.’

‘How?’ the taller shaven-head sneered.

‘Look under the table.’

The man did so and glimpsed the other arbalest the assassin had placed on his thigh. It was loaded, the barb pulled back, the finger on the clasp. The shaven-head swallowed hard and looked at his companion.

‘We meant no offence.’

‘Of course not.’

The slattern returned with the blackjacks. The cowled stranger put the arbalest down and tossed a small purse on to the table.

‘Six silver pieces, Venetians freshly coined. Three for you now, three more when the task is done.’

‘Who is it?’

‘Sir Maurice Maltravers, henchman in the household of my Lord of Gaunt.’

The leading shaven-head coughed over his beer.

‘One of Gaunt’s men?’

‘I’ve heard that name.’ The other spoke up. ‘He took a ship in the Channel. A fighting man.’

‘In his mail and armour, yes,’ the assassin replied. ‘But not in the garb of a monk. You’ll find him in the priest’s house at St Erconwald’s in Southwark, you know the place, I’ll wager.’

The shaven-heads nodded in unison.

‘He’ll be there whenever you wish. A knife in the back, an arrow in the throat…’

‘We don’t kill priests,’ the leading shaven-head protested. ‘The friar who is also there, Athelstan. He’s well known and liked.’

The assassin dug into his purse and brought out four silver coins which he placed on top of the small purse. The shaven-heads smiled.

‘On second thoughts, every dog has his day!’

The leader went to pick up the silver but the assassin seized his wrist.

‘You don’t live here, do you? You live in St Mary Axe Street. You have a sister there, or they say she’s your sister. One thing, sir, don’t take that silver unless you intend to carry out the task.’

‘It will be done.’

‘Good!’ The assassin sat back. ‘And, if the priest dies, the more the merrier.’

He drained his tankard and got to his feet. He slipped one arbalest on to the hook of his belt, keeping the other in his hand.

‘How do we tell you that your task is done?’

‘Oh, you don’t,’ the assassin replied softly, patting the man on the shoulder. ‘I’ll know and, don’t worry, I’ll come visiting you. Now, sit for a while and finish your ale.’

Then he was gone.

Athelstan celebrated an early morning Mass. Sir Maurice Maltravers, not yet changed into his robes, served as an altar boy. They were joined by Godbless and Thaddeus, who made an attempt to nibble the altar cloth. Bonaventure, of course, also arrived. The cat always stared at the chalice, his little pink tongue coming out as if he suspected it contained milk. Pernell the old Fleming woman, her hair now dyed a garish yellow, also attended, kneeling beside Ranulf the rat-catcher. Once Mass was over Ranulf came shambling into the sacristy. He waited patiently until Athelstan had divested.

‘Brother, we are all ready.’

Athelstan remembered just in time. ‘Oh, of course, the Mass for your Guild.’

‘Can it be Wednesday morning, Brother? About ten o’clock?’

Athelstan swallowed hard but Ranulf looked beseechingly at him, a gaze which reminded Athelstan that he had promised this on many an occasion.

‘What will it entail, Ranulf?’

‘Well, Wednesday is good for rat-catchers, Brother. We’ll have Mass and bring our animals.’

‘Which are?’

‘Ferrets, cats, dogs, our traps and cages.’

‘And how many will there be? I mean, rat-catchers?’ Athelstan added quickly.

He glanced at Sir Maurice who was staring nonplussed at this strange parishioner in his black tarred jacket and hood. The belt round Ranulf’s waist carried hooks, small traps and coils of wire, all the implements of a rat-catcher’s trade.

‘There’ll be sixteen or eighteen. Afterwards we’ll break our fast on a table in the porch. We will supply the food and ales. We’d like you to bless us and give a special blessing to our animals.’

‘Agreed!’ Athelstan said. ‘But have a word with Benedicta. Now, clear the church, Ranulf, and lock the door! I’ve sent Crim the altar boy across to Sir John. When he returns would you help him with Philomel, just clean the stable. Afterwards, you may finish the oatmeal in the kitchen.’

Ranulf quickly agreed and sped out of the sacristy.

‘A Guild of Rat-Catchers?’ Sir Maurice asked.

Athelstan smiled. ‘It’s a wonderful life, Brother Norbert. Yes, it’s time you changed. Put on the garb I gave you but wrap your cloak firmly around you.’

The knight hastened out and Athelstan walked back into the church. He knelt on the sanctuary steps to say a short prayer of thanksgiving followed by an invocation to the Holy Spirit asking for his help and guidance that day.

Sir Maurice had spent most of the night reading the tracts by St Bonaventure; Athelstan had woken to the young knight seated before the hearth, reciting to an owl-eyed Godbless and a rather feisty Thaddeus certain love poems he had learned. Athelstan, eager to begin his Mass, had simply cautioned the young knight on not being too impetuous.