‘Are you OK?’ he said.

‘Fine.’

He looked at the sky then out to the Forth. ‘Perfect day for it.’

They climbed on board. Ben began sorting through the rigging, checking ropes and sails.

Ellie went straight below and had a quick check to see if there was any sign that Sam had been here. She couldn’t see anything.

She poked her head back up from the cabin. Ben was loosening off the boom ties, inspecting the main sail, going through the checklist, assessing the electrics and GPS. Beyond him, Ellie could see the warehouse where she’d left Sam. She’d driven straight home, met Ben in the kitchen in front of the laptop. He’d asked about her shopping, she said she was trying on clothes, couldn’t find the right sizes. It wasn’t like her, she wasn’t a fussy shopper, or much of a shopper at all, but he accepted it.

Ben wanted to head out to the new bridge foundations. This stupid idea that they were using some chemical in the building process that somehow caused depression, hallucinations and suicide. She had a quick look at his evidence, making air quotes in her mind around that word. It was garbage. He’d gone on about the technical stuff of building, using engineering and construction lingo like caissons, piles and cofferdams, and she hadn’t really followed, especially when he got on to the dubious chemistry of the theory.

But she was here now and going out sailing with him, partly to show him how ridiculous he was being. She pointed out that if they went to the new foundations and came back without suffering hallucinations or feeling suicidal, that would surely be proof he was talking rubbish. Well, not feeling any more suicidal than usual. But he would find a way round that, reasoned argument didn’t hold sway, it always came down to ‘that’s what they want you to think’.

Ellie wondered about hallucinations. What if she was hallucinating this whole thing? What if there was no boy on the bridge, no body in the kitchen at Inchcolm Terrace, no little sister and drunk mother? Maybe the grief had finally got to her.

She went to the bin and opened it. The evidence of Sam’s presence, a Wispa wrapper and a banana skin.

He was real. This was real.

Ben poked his head in as she closed the bin lid.

‘Ready to cast off?’ he said.

‘Sure.’

Up on deck, he pointed to the stern. ‘Want to take the tiller, steer us out?’

He yanked the starter cord on the outboard and it rattled and thrummed. Ellie unlocked the tiller and throttled a little in reverse, just to get a feel for the power under her hand. Ben scurried portside and began unhooking the mooring lines, wrapping them round the cleats, keeping everything in place. He jumped on to the pontoon and untied the final rope, threw it on to the boat and scuttled back on deck, pushing away from the edge as he did so.

The bow moved to starboard and Ellie corrected for it. The boat alongside theirs was an expensive SEPA motorboat, it wouldn’t do to leave a dent in their hull.

The boat edged away from the berth into the shallow water behind. When it was clear of the pontoon Ellie switched to dead slow forward and headed towards the breakwater.

They picked up speed and headed past the low wall at the entrance to the harbour. Ben ducked into a storage box and pulled out two life jackets. He strapped one on and threw the other to Ellie. She caught it and put it on. It was standard practice to wear a life jacket, compulsory for sailing school and some races, but she didn’t know how much use it would be. She could swim better without it. When she was fit she could swim back to shore in calm weather long before a coastguard boat would make it out to rescue them if the Porpoise capsized.

Not that there would be any capsizing today, conditions were calm.

Ben undid the final hooks on the boom.

‘Coming round,’ he shouted.

Ellie was nowhere near the arm, standing at the stern, but it was good practice to shout it out. If it came round and someone was standing in the middle of the deck they’d be over the side of the boat with concussion before anyone knew what’d happened. She’d seen it once before, not on the Porpoise, but a racing boat she and Ben had crewed years ago. Some novice with a sickly pallour stood up at the wrong time as half a ton of plastic and metal came swinging, the full sail whipping the arm as the boat changed tack. He took the brunt of it on his shoulders rather than his skull, which was just as well. They fished him out the water after barely a minute, but had to return to dry land because of a broken collarbone. The rest of the crew were furious at missing a day’s racing, and the kid never appeared on the boat again.

The water today was royal blue. The colour of the sky always made a big difference, the sea mirroring what was above. On a dreich day the water was a mucky grey-brown, but today it was clearer.

The main sail was unfurled now and they tacked into the breeze. Ellie cut the engine. They would sail for a bit out to the bridge foundations, then pull the sail in once they were there, easier to control the boat that way.

Ben looked at the cofferdam around the nearest of the new bridge legs. There were three foundations stretching across the firth, one near each shore and a third one splitting the gap between them in the middle of the Forth. They’d had to remove a historic lighthouse from Beamer Rock in the middle of the waterway so they could build the foundation there. For almost two hundred years it had marked the way to Rosyth and upriver, and they’d carefully taken it down then blown the rock up to make way for twenty-first-century engineering.

As they got closer to the foundation Ellie felt the presence of it. In today’s world everything seemed smaller, more contained, lives played out in front of computer screens, the scale of everything diminishing. But this was gargantuan, human endeavour writ large, millions of tons of material shaped into an object that would be seen for miles, seen from airplanes, that would serve an actual, physical purpose. It made Ellie feel connected to the world, this harnessing of nature, even though nature could never really be harnessed, you just had to look at the billions of gallons of water under their hull to know that.

They sailed on for a while, Ellie staring at the cofferdam and the two crane-barges alongside. They passed the yellow navigation buoys that had appeared recently, a thin attempt to keep unwelcome visitors at bay. As they got closer the size of the thing became overwhelming, even though it was hardly even out the water yet. Ellie tried to imagine what it would be like when the bridge was finished.

She’d had a few close encounters with large ships in the past, but never right alongside. The girth of the oil tankers downriver was staggering. They filled up at the terminal on the other side of the rail bridge, and she and Ben had come within a hundred feet once or twice, close enough to know they would crush you in a second and not even notice.

She felt a throbbing through her body. She turned. Ben had pressed ignition and was locking the boom arm, furling the sail up.

She unlocked the tiller and aimed for the bridge leg, the propeller churning the wash at the stern. She looked back to shore but the old warehouse was tiny now, just a red dot in the distance, almost hidden against a backdrop of trees. It was amazing how little time it took on the water before you got that perspective, the insignificance of everything on shore. That was one of the things she loved about sailing, leaving the land and all the problems waiting there.

Ben had his phone out and was taking pictures with the zoom fully extended. The pictures would be fuzzy, what was he hoping to gain from this? Someone else to blame for Logan’s death? There was no one else to blame, and this was the worst of his excuses. Even the phone mast was better than this, and the school vaccinations or drug taking were far more likely.