It is not particularly early in the morning, but it is towards the end of the year 1790 and the sun is only just rising. Doctor Dwight Enys has been up all night attending a particularly difficult childbirth and is close to exhaustion; he allows his horse to set the pace as he rides along the mule track. Two men are standing together by the side of the track waiting for him to reach them. He hopes that they will not delay him; he dreads that his professional services might be required. As he approaches, he can see that they are strangers, dressed in a most unconventional style and without hat or cloak. One calls out to him as soon as he is close.

"Excuse us, sir; we are strangers here and require directions."

Dwight cannot place the accent; it is certainly not local, possibly not English, the man's slightly odd turn of phrase certainly suggests a foreigner. He brings his horse to a halt and looks down on them. "How may I be of service?"

"Are there mines hereabouts? We are looking for a mine owner or operator – someone in charge."

Too tired to do more than answer and be on his way, Dwight looks around, not sure for a moment where they are. "You are indeed strangers to Cornwall if you must ask whether there are mines! Tin and copper are the staples of this area. This is Poldark land; you need Captain Poldark of Nampara." Briefly he points them in the right direction, bids them a good day and rides on.

…..

There is a knock at the door, which is opened by a woman wearing a mob-cap and apron. From behind her a man's voice calls. "Who is it, Mrs. Gimlett?"

"Strangers, sur; men. Two of 'em." She looks Kirk and Scotty up and down and does not seem impressed by what she can see. "Yes?"

"This is Nampara? Is there a Captain Poldark here; we would like to talk with him," asks the younger-looking one.

A man in his late twenties comes to the door. "I am Captain Ross Poldark. You don't look like lawyers; I've had my fill of the law for a while. Are there just the two of you; are you on foot? My man can see to your horses."

"We are alone," says Scotty, "And we are on foot."

"Then come in, gentlemen, and we can discuss your business over a drink." He leads them through into the parlour. "I have no whisky to offer you on a cold morning, and perhaps it is too early in the day for serious drinking. Will you settle for tea?" He calls for Mrs. Gimlett to bring in a pot and sits his visitors down. "A Scottish voice is rare in Cornwall; are you both from Scotland?"

"I am from America," admits Captain Kirk.

"I got this in the fighting there," says Poldark, pointing to his scar. "And I saw too many good men die. Might I inquire whether you were involved?"

Captain Kirk has his answer, carefully devised to mislead while being technically truthful. "I should have given you my name, I am Captain James Kirk. My home town is in the Louisiana Territory, and I was not involved in the War of Independence. This is Mr. Montgomery Scott, and he is a genuine Scotsman, as you have observed."

Mrs. Gimlett comes in with a loaded tray and sets it down. "Shall I pour, sur?

"No, find your mistress and ask her to join us; she will not wish to miss such interesting visitors."

"She quit the house early, sur, as she oft'n do."

"Then send someone to look for her."

She bobs a curtsy and leaves. Captain Poldark ignores the tray and concentrates on the strange men. "What brings you to Cornwall and to my door? It must be a matter of some importance."

"It is of great importance to us, and we can make it worth your while too. We wish to trade. You do own a mine I believe?" Kirk asks.

"Wheal Leisure is on my land, and I am the principal shareholder. But if it is copper ore you want, then you must bid for it at the monthly auction like everyone else."

"No, no; it's something much rarer that we are after. Show him, Mr. Scott."

Mr. Scott opens the strange, shiny case he has been clutching and brings out a piece of crystal the size of a hen's egg. "We call it dilithium," he says. "Have yuh seen the like?"

Poldark nods. "A few times; it turns up occasionally. The miners have various names for it. It is most friable, and not considered to be of any value."

"Normally it isn't," says Mr. Scott. "We're looking for large crystals which have not been damaged; crystals that are still in the ground."

Poldark frowns. "You mentioned 'trade'; what have you to offer, assuming such crystals can be found?"

Captain Kirk answers. "Gold! We will pay generously for any good crystals that can be found." He studies Captain Poldark's face carefully, but finds it difficult to read. "To prove it, I can give you two small pieces now. The first is to buy your goodwill and pay for the privilege of our spending the day down your mine, searching." He places it on the table and slides it towards his host.

Poldark glances at the tiny bar, but maintains a poker face. "And the second?"

"That is to compensate you for not asking awkward questions."

He slides the second bar along to Poldark who picks them up. "Perhaps an ounce each and heavy enough to be gold. I don't recognize the markings."

"The '25g' refers to the weight, which is a little under an ounce. As for the other markings, that is an awkward question."

Poldark smiles for the first time. "Assuming you do find the crystals you want - which seems unlikely to me - how much are you willing to pay for them?"

"We can negotiate that, but at least their own weight in pure gold."

"You have the gold with you?"

It is Kirk's turn to smile. "We did not think it wise to carry so much about; we will produce it when the time comes."

Demelza, who has been listening in the doorway unseen, chooses this moment to come in, and the three men rise to their feet to greet her. Introductions are made and then her husband asks her if she would see to the tea.

"Oh, Ross; you aint very hospitable! Gentlemen, have you breakfasted? May I at least offer you cake? I'm sure we have a cake or two in the larder."

The two strangers assure her that a cup of tea is quite sufficient.

"So gentlemen," she asks. "Should my husband agree, when would you wish to visit Wheal Leisure?"

"Today, Mrs. Poldark," says Kirk.

"I have ne'er been down a mine, sirs, and don't intend to, but I was raised among miners. It seems t'me that to find what you seek be mighty difficult and liable to take weeks."

Kirk gives his most winning smile. "A good point, Mrs. Poldark! Fortunately, we have a means of divining the location of a crystal. If there is even one good crystal in the mine, we can find it today."

Leaving their guests in the parlour, Ross and Demelza move to the kitchen to discuss them in private.

"Ross, where did these men come from? I've ne'er seen anyone like them. They seem to be wearing some sort of uniform of a cloth I've ne'er seen afore. And they are so smooth of face – they must have been shaved this very day."

He nods. "If there was just the one, I'd think him an escaped lunatic; but two? They may be members of some strange religious group."

"Are you going to take their gold?"

"They seem harmless, and our circumstances are strained. I'd be mad not to follow this seam and see what it yields."

A few minutes later, Captain Poldark is striding towards the Wheal Leisure mine with the two men, answering their questions as best he can. They pause by a spoil heap, and Mr. Scott produces his divining device, which he called a 'tricorder'. "This is encouraging," he pronounces. "There are signs of many fragments in the pile."

Poldark finds his friend Paul Daniel, a miner he can trust, and instructs him to escort the two men down and around the mine. "Take them wherever they want to go or see. Answer their questions and look after them; I doubt either has been underground before. They are to look only, is that clear? They are to take nothing away with them, not so much as a pebble!"

Having handed over the two men, he hastens back to Nampara and instructs Gimlett to saddle his horse. "I am riding to Truro to find whether these little bars are the real thing or fairy gold. You are to ask around, ask if strangers have been seen recently, what boats have come ashore."

Meanwhile, Kirk and Scotty are going underground with lighted candles on their hats. For the next three hours, the two 23rd century spacemen climb up and down greasy wooden ladders, shuffle stooped along narrow ill-ventilated tunnels and wade through chilly pools of murky water. In that time, Scotty gets a fix on just two crystals of any quality; they are far below the current diggings and might be impossible to reach. Tired and discouraged, they clamber up to daylight and the fresh air blowing in from the sea. They trudge back to Nampara, muscles aching.

Ross Poldark is in good humour; the two little bars were gold of the highest purity. The two strangers are invited to dine, which they readily accept. Over the meal, they explain to the Poldarks that they must look further afield and ask for advice on whom to approach next. Poldark is reluctant to let them go. In particular, he does not want them and their gold getting into the grasping hands of the Warleggans. "I do have a second mine; it hasn't been worked for years, but I can take you down this very afternoon. The autumn rains will have filled the lower levels, but there is still plenty to explore. The old diggings are extensive."

Soon, fortified by a little of Captain Poldark's brandy, the three men are at the entrance shaft to Wheal Grace. "Can you swim?" asks Poldark. "There is a lot of water down there, and only the three of us if one falls in. Go carefully on the ladders; there will be rotten rungs. I'll go first."

Down below, Poldark watches in fascination as Mr. Scott uses the tricorder. "Mr. Scott, a question if you please; can your device be used to divine for other minerals, or is it good only for your crystals?"

Very soon, Scotty is pointing out where a rich lode of copper ore is to be found. Captain Poldark is impressed that this agrees with what Mark Daniel had told him before his escape to France. Minutes later, Scotty and Kirk are elated to discover that the single intact dilithium crystal they have detected lies in a tunnel roof, only inches above their heads. With the delicacy of a brain surgeon, Mr. Scott extracts the crystal and fits it into the special container he has brought with him.

Back at Nampara, Mr. Scott and Captain Poldark go inside while Captain Kirk hangs back. Poldark hears Kirk talking to someone, though there is nobody about. When Kirk comes in moments later, he is carrying something which he did not have earlier and places on the table. "I hope, Captain Poldark, that we need not bicker over our agreement. I have here two gold bars ten times the size of the two you already have."

"Generous indeed, but I would swap one of them for your tricorder."

"That is not possible, Captain. Even it were, I would advise against it; you do not need it to find copper or tin. You have your own expertise in that. As for dilithium crystals, we have found all we need, and you will have to take my word for it that you are most unlikely to find another buyer."

Poldark has come to trust Captain Kirk, despite his lack of openness, and the two captains shake hands. Pleading the need for haste, Kirk and Scotty say goodbye to Ross and Demelza and leave. They are not seen again, disappearing as mysteriously as they arrived.

Demelza asks Ross if he is certain this gold is as good as the first. He grins back at her. "I am certain of it. I shall take one of these bars to Bodmin; I'll get a better price for it there, and no questions asked. The other I'll keep in case of dire necessity."

"Will it pay off all our debts, Ross?"

"No, but my impending bankruptcy is at least delayed. More importantly, I have the confidence to re-open Wheal Grace, now I know there is copper to be found there. There is war with France coming and the price of copper can only rise."

…..

On the USS Enterprise, Scotty and Kirk are checked over by Dr. McCoy as soon as they arrive via the Transporter. "You could be bringing aboard anything from smallpox to tapeworms, Jim. Not to mention fleas and lice." As soon as they are cleared, Scotty hurries off to Engineering to get the new crystal installed and tested. Kirk stays chatting with his friend McCoy, and tells him of their brief experience of King George's England. McCoy is amused that it was the striking young Demelza Poldark who made greatest impression on the Captain. He suggests that Kirk have a little present for Demelza transported down.

The dilithium crystals have to power the warp drive along the sling-shot trajectory Spock has calculated while maintaining the deflector shield at full power as they skirt close to the sun, so there is much to do before Scotty and Spock are satisfied that the crystals will hold long enough to get them back to their own time. Then the course is fed into the navigation computer, a present for Demelza is beamed down, and Captain Kirk gives the order everyone on board has been waiting for: "Helmsman, take us out of orbit. Enterprise is going home!"

…..

In Nampara, Mrs. Gimlett presents Demelza with a strange object she has found at their door. "Whatever is it, mum?"

Demelza laughs out loud, amazed and delighted. "Why, I have seen one afore, at the Warleggan's grand ball. They made a great fuss 'bout havin' one; 'tis a pineapple!"