Kit waved at him from outside. Tom managed to smile at the lady, who made no attempt to conceal her interest, staring at him with an arch expression as she counted through the notes, and he lugged the sack of potatoes out to the cart, where Kit was already loading up.

The horse blew out a deep breath as they finished, and a single decker bus in a dark green livery, looking old and weary, chugged up to the bus stop. It was full, mostly of people going shopping in the market town. Kit flinched, as if he could not stand the sound of the engine, and turned away.

An elderly lady with two sticks took her time getting off the bus, followed by a woman who seemed to have three or four children in various states of undress and with varying degrees of lollipops in their mouths, a small terrier-like dog yapping at her heels. The mother dropped her wallet, and someone hurried out from the bus behind her, thrusting a soft toy at her which had been left behind.

An idea came to Tom. Kit was busying himself with the packages. He dropped the bridle and sauntered over to the bus stop. And then, casually, he stepped up onto the bus.

‘Ticket?’ said the driver.

‘To the town, please.’ Tom felt in his pockets for change. His hands closed on a two-pound coin.

Almost immediately a terrible pain hit Tom in his stomach, and he doubled over. His vision went black. He grabbed on to the bus pole.

‘You all right, son?’ The driver, though concerned, was looking at his watch. Everyone else on the bus was either staring out of the window or tapping their feet. Somebody rustled through their shopping. A child asked, ‘Why are we waiting, Mummy?’ and then kept repeating ‘Mummy’.

Kit came over. He grabbed Tom by the shoulders, helped him off the bus and sat him down gently on a bench by the stop.

‘Is he getting on or not?’ The bus driver sucked in his teeth.

‘Not,’ said Kit thickly.

The driver wrenched the bus into gear.

As soon as it had puttered round the bend of the road, Tom’s pain vanished. He managed to stand up.

Tom didn’t need to say anything to Kit. He knew what had happened. That was James, pulling him back, stopping him from going any further. He’d felt the wildness, the darkness.

James Swinton, his own flesh and blood.

The realisation hit him: he was trapped. He was a captive too, in the farm on the island.

Now he understood the sign on Zita’s blazer, the square within the square. And within that square, another square, and so on, and on until there was nothing.

They were all trapped – he, Kit, Zita and the Captive – in Jack’s web of power, and he was the spider at the centre, feeling the tension on the strings.