Now Forest was certain what lay beyond that jagged slash in the rock. He almost didn’t want to look, but he had to. He’d come too far. He imagined her, sticking her arm through after Huck, pushing the slate ahead of her, hoping that someone would find it . . .

He carefully poked his upper half through the narrow opening, scared of getting his shoulders stuck but finding he had plenty of room. He wondered how big Forest Dempsey had been that he couldn’t fit through this space – unless erosion had widened the tunnel in the years since?

Through the gap was a drop down to a larger area, with water pooling at the bottom. It stank of brine and sea.

His torch beam landed on two corpses, arms and legs akimbo, picked clean of everything but their clothes and pieces of scalp by sea lice. The bodies were gunky, the larger one missing its bottom half, the smaller skeleton missing its bottom jaw. A rusting scuba tank lay in the corner, pitted and broken.

Here lay Forest and Alexandra Dempsey.

Don’t be sad. It happened years ago. And it has nothing to do with you.

The thought came from a distance. Forest felt like he was seeing this scene through someone else’s eyes. His own mind had disappeared way up into the stars, his ears buzzing, the taste of copper in his mouth.

Clutching the diving slate, Forest walked all the way back to Safe Harbour. His body was still shaking, his breath hitching in his throat. He tried to force himself to stay calm, but it felt to him that the whole walk happened in fast-forward, without conscious thought.

When he finally climbed into bed, it was only Zeus whimpering and licking his face that brought him back to his body, back to the present. He couldn’t remember climbing out of the cave.

‘How did I get out?’ he wondered aloud.

Exhausted but uncertain of how much time had passed, he feared dawn would come all too soon.

He looked down at the slate. He had the coordinates to what Alexandra had labelled as ‘the Bone Cave’. He didn’t like that wording. He’d refer to it as the Treasure Cave.

But to see it for himself, to get down to the bottom of the ocean, he’d need to learn to dive. Mackerel would be the obvious choice for a teacher, but maybe there was a way to use this situation to his advantage . . .

Ahab was a trained scuba instructor, and he was very invested in protecting him.

For as long as he thinks I’m Forest Dempsey, at least.