"No. The only way down to the cove itself is a steep set of stairs carved out of the rock: it's completely surrounded by cliffs. There's a small boathouse on a ledge at the bottom, a slipway slanting down to the beach, and then the sand itself. That's all. At the moment, there are about ten lines of rollers sweeping into the cove — it's one of those long, narrow ones — and the sand looks pretty wet!"

"You've got the Tor behind, cliffs and fields on the far side of the cove, and this house in the valley. What's inland — beyond the house?"

"You can see the road climbing the valley until it reaches the moor — where the land has dropped away from Trewinnock Tor. And then the moorland itself seems to have flattened out a bit there. I'm just... Oh, yes! Mark, I've just rounded a rock outcrop and of course you can see the whole DEWS station laid out before you, where the moor flattens out. The masts and reflectors are about a half mile inland from Wright's house — he must have a marvellous view of them! — and the blockhouses and everything are another quarter of a mile beyond that."

"Then the road to the house must be a private road, just going there and nowhere else, which passes fairly close to the station?"

"I guess so... Mark, I'm leaving the path now. There's a stile with a footpath leading inland and a notice saying that trespassers will be prosecuted... I'll call you back."

Fifteen minutes later, Slate was summoned to the Communicator again by another series of bleeps.

"Mark!" — the girl's voice was full of suppressed excitement "I've just seen the man himself. He's out with a shot gun — and believe it or not, he's actually wearing tweed plus-fours... you know, those baggy Norfolk breeches that tuck into woollen socks! He looks like a New York ad for whisky!"

"Has he seen you?"

"Oh, yes. He waved and he shouted and he tried to warn me off in various ways — then he started to come towards me, since I steadfastly refused to understand him. A moment ago, he started shouting something again, but I pretended not to hear. He's down in a dip now — we're quite near the house — and as soon as he breasts the rise I'll have to stop talking."

"What are you going to do?"

"Turn on the full charm" — her voice was low and hurried

— "and see if I can persuade him to ask me in for a cup of tea. After that, I'll leave it to my intuition! I'll keep my eyes open, see what information I can get by playing the dumb brunette, and generally play it by ear."

"Yes, April, that's all very well, but—"

"Oh, hallo! Do please forgive me, but is this private property? I'm trying to get back to Porthallow without going along the cliff path — I do suffer from vertigo — and I'm afraid I must have lost my way." The voice was loud, a little brash, inexperience hiding behind a mask of over-confidence… but it was still unmistakably April's. Slate instantly switched off the "Send" button on his Communicator but left the aerial extended.

"My dear young lady!" Sir Gerald Wright's voice was equally recognizable. "There are notices absolutely all over the place!... Still, as you're here, I suppose…"

"I'm most frightfully sorry... so stupid of me. If you could kindly point out the right way to me..."

"You might have been winged, you know. I've been shooting. Those notices are there for a reason... No, I'm afraid the cliff path is the only way back to Porthallow from here — but one can hardly allow a beautiful young lady... a very beautiful young lady, if you'll permit me... to suffer vertigo on account of that. I'm going into town later. You must let me run you there in the car. You're not in a hurry, I hope?... Anyway, we'd be there as quickly as you would walking all the way along the cliff."

"Well, gosh, that's terribly kind of you... but, I mean, I hardly like to..." April's nicely judged blend of reluctance with the eagerness of a young woman flattered by an older man would have drawn appreciative smiles from the histrionics instructors back in the U.N.C.L.E. building in New York.

"Not at all, not at all, not at all." Wright's smooth tones were overriding her. "I must positively insist, my dear young lady. While we're waiting... I have to — er — wait for a telephone call, you know... I shall show you over my little place we have a splendid view... and perhaps you'll join me in a rather early aperitif, eh? Splendid!"

"Well, it's terribly kind of you..." April began again, and then — no doubt as they turned to walk up towards the house — there was a click and the Communicator went dead. Presumably she'd put it back in her handbag with the numerous other gadgets she carried there, Mark thought with an inward smile. Oh, well — good luck to her... In the meantime, he had some chores to attend to.

Tucking the little transceiver into his breast pocket, so that he would run no risk of missing the signal if she should call again, he ran down the steps and off towards the sideshows and the gate. There was no sign of life from the converted pantechnicon next door: presumably Curnow had taken the locker of photos and gone.

Back at the harbour-side inn, the receptionist told Slate that there had been a telephone message for him. Asking her to call back the number, he slipped into the below-stairs niche that served as public phone booth and waited for the connection to be made. Through a small window, he could see spray exploding over the sea wall like infrared shell bursts against the darkening sky. The tide was almost high and the craft riding at anchor there rose and fell uneasily as the unaccustomed swell flowed in between the breakwaters.

The message had been from the laboratories in Truro to whom he had consigned the white powder they had scraped from the secret compartment in the lighthouse. The voice on the line was crisp and businesslike over the West Country burr. "Mr. Slate?... Sorry to trouble you to ring back, but I thought you might like to know — and a letter won't reach you until Monday. We have some information for you here... though I'm afraid it's negative rather than positive, if you see what I mean!" The voice chuckled. "Only you won't see what I mean until I've told you."

"I'm sorry," Mark said patiently. "I'm afraid I'm not quite…"

"Not quite with me? Not to worry. Happens all the time! The point is, that white powder you sent in for analysis is nothing whatever to do with any drug. Absolutely not."

"Oh. All right then: what is it?"

"Nothing more nor less than Serpentine dust, old boy! The fragmented residue of a veined igneous stone peculiar to these parts, I believe. Mixed with a very small quantity of carborundum dust — which leads me to suppose that your lighthouse gathered its dust either in the place where it was made or one very much like it. It was a Serpentine lighthouse?"

"No. It was made from Porphyry, actually — but Serpentine dust could easily have blown into it if it was made in the same workshop, I suppose. You do mean to imply that this dust — and the carborundum — comes from the wheel they use to turn these souvenirs?"

"Couldn't swear to it, laddie — but say I'd be very surprised if it wasn't, eh? The dust and chippings look much lighter than the original stone or the polished article, you know."

"Understand. Let's take it, then, that it's a natural place to —"

"There is one other thing, though," the technician was saying. "It turns out that there are also minute — and I mean really small — traces of film stock celluloid in amongst the powder."