"Oh, Point Number Three. Definitely. The more I think about it, the more I'm convinced. Even in the short time I've been talking to you about the affair, I've become practically certain of it. And anyway, nobody has taken a pot-shot at Curnow, so why try to bend an unknown assistant unless you have some further reason for rubbing him out?"

"Yes, that makes sense, I'm afraid. Have you found out anything about the attempts themselves? How they were worked, I mean."

"As much as one can. The shattered window on the car has been taken out — witness the draught howling in over my arm! — and I retrieved the slug from the door trim on the other side. I don't want to tip off Curnow that there's anything out of the ordinary about me — at least not yet — and so I can't very well get the bullet to a ballistics expert down here. From my own limited knowledge of the subject, I should judge that the gun was an express rifle, as I suspected — probably a Mannlicher — that it had been fired something over a thousand yards away, and that, if you produced the line between the place where the bullet lodged in the door and the opposite window where it entered, it would slant up over the tents to the moor above the town."

"And would the place where this line hit the moor be a thousand yards away?"

"Give or take a hundred in each direction, yes. But it doesn't really help: there's an awful lot of moor, and a great deal of it's a thousand yards away from the circus field! A two degree error in the arrival line of the slug — even if I'd estimated it, which I didn't — would give you a quarter of a mile or more up among those rocks. It was useless looking — and it could have been anybody, anyway. Anybody but Curnow, that is: he was with me!"

"And the case of the rolling stone?"

"Easier to pinpoint what happened; just as difficult to pin it to a person. The boulder was one of those local rocking stones. It had been perched about fifty yards above the road, on the hillside — just far enough for it to get up speed as it burst through the hedge and took the bank. Someone had worked it almost over with crowbars — you can see the marks in the turf — so that the smallest push would topple it down the slope when required."

"But how did they know when it would be required?" she frowned.

"Given the fact that my cover is blown in some way, it's not so very mysterious. First, they would be watching me any way. Secondly, if it was known that I was professionally interested in Sheila's death, it was a reasonable bet that I'd be going to see her fiancé — and the lane is the only road to his hut, where he spends most of his time. Thirdly, I hadn't been especially discreet about hiding the fact that I wanted to see the boy — at that time, there was no need to be. Fourthly, this car is somewhat distinctive and the lane is in full view of the place where the rock was. All they had to do, once they knew I'd be going there, was wait."

"Even so, it's a pretty crude, imprecise method of trying to… I mean, compared with a high-powered rifle, it's a bit of a hit or miss —"

"I know what you mean," Mark interrupted. "But it's not all that bad if you think of it merely as a means to try and frighten someone off."

"Oh, you think that's what it was?"

"I think it might be. The rifle shot could have been a deliberate near-miss for the same reason. When you think of it, the boulder idea is so melodramatic, so unscientific, so unlikely to succeed because there are so many variables — the car's speed, the boulder's speed, the terrain, the direction, for example — that it would seem absurd for anyone to try it if they seriously wished to kill or maim their victim. In particular for the sort of person who dreamed up the rifle idea and the coconut-shy routine."

"I see. Any idea of the perpetrator, just the same?"

"It's wide open. Practically the whole town used that road yesterday afternoon for some reason! It leads to the Coverack road over the Tor."

"Could they all have done the trick with the stone?"

"Most of them could! The hut where the fiancé turns his Serpentine lighthouses is a couple of hundred yards away; Wright's house is just over the brow of the hill, looking towards the radar station; Curnow used the lane only a few minutes before me, on his way to St. Keverne; the landlord of the pub brought some stuff down it in a shooting brake just after lunch. Even the Harbourmaster was out walking, it seems!"

"How many of them could physically have done it, time wise?"

"Provided they had already loosened the boulder in anticipation, any of them."

"Oh, dear," the girl said. "Dead end. What do you suggest then?"

"I suggest you leave that to me. It'll already be known that I'm meddling in something, anyway. So far as you're concerned... What did you say your cover was?"

"I hadn't yet. New Zealand girl, ex-university graduate, ex-barmaid, working her way round the world, on the lookout for any employment. Waverly hoped the antipodean bit might excuse any departures from the norm in my English accent!"

"But that's perfect!" Mark exclaimed. "Old Bosustow was complaining every five minutes how difficult it would be to find someone to take over the booth Sheila had, at this time of the year. With that background, you can quite legitimately go and see him and ask if he's any work. You've come to the southwest because London's too cold for you in the winter.

"And when he says he hasn't anything, but there's a concession you could operate — well, you can say you have a little money saved, or offer to pay later, or give him a percentage of the take... anything, so long as you don't appear too eager. Then, if only you could get installed in Sheila's place, we could take it from there: the booth's as good a place as any to start, so long as we restrict any double appearances, as it were, to after dark! Maybe we could even solve the mystery of the burglars who take nothing!"

"Yes. I think that's a good idea," the girl said. "At least, I'll give it a try. Where did Sheila live, by the way?"

"She rented a small two-berther from the old man. I guess you could have the same caravan if the deal comes off. And talking of coming off, here's where you'd better think of getting off. This is Helston."

The streets of the market town were bordered by wide channels carrying the brick-red waters of a stream, and after the granite and slate of Penzance the whole place seemed warm and pinkly bustling in the afternoon light. April extricated herself from the Matra-Bonnet's passenger seat, reached in for her suitcase and the black crocodile handbag, and leaped nimbly across the surging gutter to the sidewalk.

"You can pick up the bus down the first side street to the left," Mark called as he leaned over to shut the door. "It'll be labelled 'Falmouth via Porthallow' — and the fare'll cost you half a crown — if you know what that is!"

"Thanks. I'll keep in touch by radio — but you watch out for ladies in jodhpurs in bars!" the girl called.

There was a momentary squeal as the wide Michelins bit into the asphalt, two small puffs of smoke — and the blue car was rocketing towards an intersection and the main road to Falmouth and the east.

CHAPTER SIX: THE CUSTOMER IS ALWAYS WRONG

THERE was nothing to show the casual passer-by that Mark Slate was in the middle of a two-way radio transmission. He sat slumped in the driving seat of his car, apparently gazing idly at the folds of moorland sweeping down to Porthallow and the twin curves of breakwater enclosing its harbour. To the more inquisitive, venturing closer to the lay-by on the slope of Trewinnock Tor where he was parked, he would have presented the picture of a young man intent upon some task for which he had specially stopped. For there was a notebook, open at a page half covered with handwriting, propped against the steering wheel — and he was toying with what looked like a rather fat pen.