O’Neill’s short laugh was rather bitter.

“Too large for you!” he said. “If that’s the case, it would be rather an out-size for me, I should say.” His look travelled over the two tall lads, wiry and powerful. “Unless—it isn’t money, I suppose, Jim?”

“No, indeed; it’s brains!” Jim answered. “And we haven’t got any. Anyhow, we don’t know how to handle this situation.”

“Well, I’m at your disposal,” Sir John said. “Fire away—there’s plenty of time before dinner.”

“We’ve found a little submarine supply-depôt,” Jim said. “What does one do?”

O’Neill dropped his brush, and stared at him.

“You say it much as you might say, ‘We’ve found a mushroom: how do we cook it?’ ” he uttered. “It isn’t a joke, Jim?”

“Indeed it’s not,” the boy said, quickly. “It’s because it’s so horribly serious that we’ve come to you.”

“But—where?”

“In a little inlet about a couple of miles up the coast,” Jim said. “Funny little shut-in place: you could sail past it outside and never notice it, the headlands are so close together.” He described their discovery briefly.