“Yes,” Matthew said. “Before that I hadn’t really said two words to the others—not any of them. But the trip changed that—I think we all felt exactly the same. We came out the other side a little different—a little older. And we felt we had some kind of bond because of it.”

“What about the other kids? The ones that were in the class but didn’t become part of the ‘group’?”

“Some of them didn’t get it. Some of them hated it. Two of them even had to get off.”

“I’m sorry—get off? How would someone ‘get off’?”

Matthew looked at him as though it were obvious, but seeing Robin’s confused expression dropped his. “Sorry, I forget people don’t know, but you wouldn’t if you hadn’t gone through at least once. When you go on a trip through the tunnel—if you’re going on one of the tour boats, anyway—there are four pilots that go through with you. Two are drivers—one at the front and one at the back—one is the tour guide, and the last takes a van through the abandoned rail tunnel next to the canal tunnel. There are half a dozen cut-throughs between the canal and the rail tunnel where the guy can appear and ask if anyone wants to get off. Say someone’s suddenly claustrophobic—panicking, screaming, I had someone projectile vomiting once—the driver can take them back in the van far quicker than the boat can. And that way, everyone else can carry on.”

Robin wrote down Abandoned Rail Tunnel—this wasn’t a mystery of one tunnel; it was a mystery of two. If someone could’ve got into the abandoned tunnel, they would have had access to both. He paused, then wrote down Other workers?? too.

“Let’s get back to the group,” Robin said. “You seemed to all be quite loved in Marsden. Why was that?”

Matthew shrugged. “I think the ‘grown-ups’ liked to see young people not acting like hooligans. We were a ‘gang,’ I guess, in the true sense of the word, but we didn’t go around making trouble for anyone. We kept ourselves to ourselves mostly, and when we didn’t, we liked to help out around Marsden. Marsden is my home—I love it—so I like to help out any way I can. We used to do charity events, help out at the old folks’ home when they needed it, stuff like that...”

“You were proud of the group?”

Matthew frowned. “Of course. What kind of question is that? They were my best friends and we were good together. At least... Nearly ten years of friendship and then...”

“You said it was Tim’s idea that this year be the final trip? Do you know why?”