Howard hurried after his grandma. He didn't like it when she was in one of these moods. She was unpredictable, and Howard knew not to get on the wrong side of her unless he wanted something to go seriously wrong.

Not like anything had gone wrong already.

Up ahead, his grandma was mumbling to herself. She seemed to be repeating 'Johnathan Coyle' over and over again, as she scanned the surrounding headstones with her torchlight.

Howard shuddered. Not only was it cold, but he hated cemeteries and his head was pounding from the blow the blonde woman had landed on him.

"Aha," said Carabella. "Here. This is the one."

Howard peered down at the headstone she was shining her torch at. It looked new like it had been placed there not long ago. He looked at the engraved words and realised with a jolt that Jonathan had been fifty-eight and had died this year.

Howard shuddered.

"Dig," snapped his grandmother.

He looked up in surprise. "What?"

"Dig," she repeated. "Dig up his body."

Howard glanced at the headstone in alarm. "But ma—"

"Dig!" roared the woman. "Dig or I'll whack you with the shovel!"

Howard gritted his teeth as he took the shovel from his grandmother's hands and started to dig.

He thought about that young woman as he worked. Eleanor. The one who'd whacked him with a lamp and caused his head to blow up angrily. He still felt the throbbing pain in his temple as he dug up every shovelful of soil.

"Almost there. Almost there." His grandmother cackled, which made Howard shudder again. He hated it when she laughed like that.

But his grandmother had always been very strange. She lived alone in a house by the sea, didn't want anyone living with her because they said she was dangerous. But none of that was going to stop Howard's father. His dad, being a doctor, didn't understand much to do with sentiment or emotion – it was probably the reason why Howard's mum left him. He saw the hard facts, one being that his mother's house had been available and that he needed somewhere to send Howard for the summer. Just two weeks, he'd promised Howard. You'll be by the sea – it'll be a lovely break.

Howard knew his father's real reason for sending him south was to try and fix a fractured relationship. His father and his grandmother never got on – Howard hadn't heard many details but the tension was clear as day. Howard's grandmother was a tough nut, someone you didn't mess with, and so this was his father's attempt at a resolution, by sending her his son as an apologetic gift.

As soon as Howard had arrived at her house in Devon, she had been fussing around him, telling him that they had to prepare for their exciting journey. This surprised Howard – he had been expecting boring shopping trips or long hours fishing only for it to start raining and for them to catch nothing; something far from the buzz of London.

But his grandmother had been full of energy. They were going to bring justice to the world, she'd said. They were going to bring justice by bringing down three men, starting with a lonely farmer and then a man named Jonathan Coyle and finally someone who Howard did not know. His grandmother had not told him the name of the last man. She said she'd forgotten it herself but would surely remember when she reminded herself of the crimes he had committed.

These men, it seemed to Howard, had all done something bad.

Starting with that farmer. He'd cheated on his wife, or so that's what Carabella had told him. She'd known his wife well, seen the suffering he'd inflicted on her, and this was his grandmother's call to change.

By killing him.

She'd loaded a gun and crept into the man's house. Then she'd fired into his brain and let the blood pool onto the floor of his bedroom – at least that was how Howard imagined it. He had been outside on a look-out, shaking uncontrollably like he was now. He remembered the flutter of birds that had been roosting on the roof as the shout rang out into the night. Then Carabella had crept out holding a body, and they'd buried him in the garden. Howard had vomited a short while later.

Howard shuddered again. Every single night after that one, his dreams had been infested with the event – it churned in his subconscious constantly. He wondered what the other two men had done and if they would haunt him in the same way.

"Keep digging," Carabella was murmuring. "Dig, dig, dig."

Howard drove his shovel into the soil again. It was easier now; the soil had been turned over recently. Perhaps Jonathan Coyle had been buried not that long ago. Yes, Howard decided. That was probably it. Before he could let any stupid fantasies get into his head, he'd tell himself that Jonathan Coyle had died a while ago. Eleanor had done the job for them. Nothing else.

It was only a second later that his shovel banged against something hard. Carabella's eyes lit up and Howard swore he saw balls of light gleaming in the darkness.

"Keep at it!" she said excitedly. "We're almost there! Almost there!"

Howard bit his lip as he widened the hole and scraped away the soil covering the wooden box. He expected Carabella to tell him to stop so that she could look at the coffin but she only looked at him expectantly from the top of the grave.

"What are you looking at me for?" she snapped. "Open it."

Howard could feel the blood draining from his face. His fingers gripped on the shovel.

"Grandma," he pleaded.

"Open it, Howard. We need to see if it's really Jonathan Coyle."

Howard let himself give a little whimper but he did as Carabella had asked, and knelt into the grave, soil dampening his jeans. He fumbled round the side of the wooden box, wondering if there was some sort of latch.

"Open it."

His hand caught on something. He wrapped his fingers round it, closed his eyes, and pulled. The lid gave way, rising upward and over. Howard's eyes were still closed. He refused to open them. There was no way he was to look at another dead body again. That farmer had been enough. But this? No, he couldn't deal with more blank eyes or pooling blood; his dreams projected plenty of that.

His grandmother's gasp made his eyes flicker open.

"What is it?" he croaked and he turned to her, not wanting to lay an eye on the body. Carabella's eyes were wide as she stared into the wooden box behind him.

"It's not there!"

Howard felt a small pulse in his ear. It was threatening to grow any second.

"What?"

"The body." Carabella gasped. "It's not there!"

Now Howard turned to look. He lowered his eyes and confirmed what his grandmother was seeing. There, in the damp soil, illuminated by his grandmother's torchlight, rested an empty coffin. No body wrapped in linen sheets. No prized possessions lying next to him.

Nothing. Just an empty coffin.