“Not those muscles!” Ark sighed. “Freshwater mussels, glowing in the dark!” He remembered the shells, opening and closing like a million pairs of hands in the deep water shaft. Diana always provided, even down here.

“So, you can get ’em down yer? Yeah?”

“Yes, of course!” said Ark. He sat down next to Mucum and tucked in.

Mucum looked doubtful for a second, until his stomach got the better of him. After the first slurp of the nutty, briny liquid, he was won over, even forcing himself to chew the rubbery lumps. “This is a bit of all right!” he finally managed to say, dunking a lump of dark bread in the bowl to mop up the remnants. “In fact, I’m almost starting to feel like a Dendran again! Time for Plan B.”

“The Councillor’s men know I’m alive,” said Ark. “That makes me a target. But they’ve never seen you.”

“What, so you stay down ’ere livin’ the easy life and I’ll jes’ climb back up and get myself a few arrows in the gut? Thanks, mate!”

There was a knock on the outer door and Joe came bustling in. “How did yow loike our Flo’s hot pot?”

“Very nice. Thank you,” said Ark. “Joe …” Ark didn’t know where to start. Mucum was no help, avoiding his eyes. Ark tried again. “We’re in trouble. Or rather, Arborium is in danger. Traitors are going to overthrow the King at the Harvest Festival and destroy the island. And we’re the only ones who know.”

Joe frowned for a second. But his bleached white face couldn’t stay miserable for long. “Yas! There’s always strange goings-on up top. Never really concerns the loikes of us when there’s work to do!” He smiled again, as if all thoughts of revolution had dissolved into water. “I been prayin’ for a couple of helpers for many a day and ’ere you are, landin’ roight with us! Yow’ll be joinin’ me today, Oi think.”

“But we have to leave.”

“Leave! Leave! Yow must be kiddin’! Yow’re a gift, eh, miracle boys?” The subject was dismissed. Joe held the door open. “Are yow comin’ or what?”

Mucum shrugged his shoulders. If one of their treenage girls could pick him up as easy as a sack of potatoes, he wasn’t going to argue.

Ark didn’t know what to do. Either adults wanted to kill him because of what he knew, or they laughed off his concerns. The whole wood was going mad and it looked like they were both prisoners of the politest, strangest creatures he had ever come across.

17• DIVING DEEPER

Joe bowed and gave his hands a fluttery flourish as he ushered the boys forward through the door. “Welcome to Joe’s Divin’ Station!”