We had nearly forgotten about the locked single-storey building in the alien city that we had christened Metropolis. Mrs Diane Kempe, my wife and head of security for the human colony, had surmised that it was an armoury, but it could just as easily be a jail, or a police barracks. Just because a building is locked securely, doesn't make it a repository for weapons.

That was the argument I had made, to encourage her to leave it to one side while we explored the remainder of the city. That ruse had been successful, but then none of us thought about it for a while: there were always more interesting things to explore and investigate, such as the possible conversion of alien housing into homes for humans. That story has been told elsewhere, so no need to bore you with a repetition. Suffice it to say that it ended up providing steady work for a large gang of plumbers, and a squad of furniture restorers.

It was not until we made a conscious decision to move the colony administration headquarters to the city that the question returned. We finally moved from our original settlement, named Homewards. The move had become possible by the establishment of a rail link between the two locations. We expected Metropolis to become our capital city, as it could contain thousands of people eventually.

So we moved into the Governor's mansion. Perhaps I should have mentioned that my name is Bob Kempe, and I am the appointed Governor of the planet Home, which eventually would be named Rehome. I have three wives, through no fault of my own. Diane, my original wife, picked our black South African friend and colleague Ruth, a psychologist, to become my second wife once we moved to start a colony on the planet we called Home. We had decided that Home's laws would be minimal, and the marriage laws would not be restrictive, except in demanding that all partners love each other, and signed a binding document to that effect. Failing to live up to that was sufficient grounds for divorce with no financial benefit to the person responsible for the breakup.

Anyway, to explain the circumstances, Ruth's social background in South Africa meant that a woman pursuing university education became "too old" to be marriageable material, and Ruth was resigned to that situation. Diane decided that Ruth was a nice enough person to join us in matrimony, and our friend jumped at the chance. So we became three, and that was fine. Our final spouse was a surprise, in that no one was expecting her to join us. Mary appeared first at our medical facility, as a patient suffering from depression, partly evidenced by her fear of men. Ruth was called in to assist the male doctor, who could not even get to speak to her in a one-to-one situation. Ruth was able to hypnotise Mary, to get the background story out of her. It was a sad tale of joy turned to despair. She had been married to a man she loved, and was expecting their child. Her parents died in a car crash a few months prior to the birth, and it was only sheer luck that prevented Mary from being with them at the time. Then at the birth, Mary's baby died through strangulation by the umbilical cord, and her husband's car was struck by a juggernaut lorry while he was on the way to the hospital, and he was killed outright.

The convergence of all these disasters at the one time drove Mary almost insane, but she recovered enough to decide that a new life in a new colony on a new planet would do her good. As she excelled in her chosen profession as a chef, but could not get a senior post in any good restaurant on Earth, she sought a chef's job on Home, and found a welcome in the colony's main kitchen that served the community as sole public eating-place, known as The Canteen. It was from there that her symptoms returned, and she sought medical help.

She was such a top-class chef that I, Bob Kempe, as the Governor of the colony, selfishly decided that Mary could continue her treatment under hypnosis in the Governor's mansion, provided she acted as the Governor's personal chef during that time. It was a mutual benefit deal, and worked for some time until Mary's subconscious misinterpreted Ruth's instructions under her hypnosis treatment. To everyone's surprise, she manipulated a situation to have her made love to by me in the dark, under the impression that she was Diane or Ruth. That almost disastrous adventure nearly had her sent away, but when the result was pregnancy, Diane decided, with Ruth's advice re her mental health, to allow her to stay. Mary begged to be allowed to marry me, but Diane insisted that the decision would be made by her and Ruth, and would depend on Mary's mental improvement and her ability to get along with the other two women. She achieved both aims, and later was allowed to marry me as my third wife, with the proviso that she remain as the Governor's personal chef, on my paid staff.

So that in a nutshell is the background to me having three wives. I did not deserve or plan to be in that situation – it happened to me, and I went along with Diane's wishes. All three were expecting babies by the time of the third wedding, so we were going to be a large family. Diane by now had had her baby, a son whom we called Robert, and was well on her way to our next child. Diane had been a colonel in US Special Forces ( a unique situation) before we married, so she was a bossy type, always wanting to be in charge. She was made head of the Rehome Security Services. Ruth was a professional psychologist, so she was called in for her expertise in various situations; and Mary was in my opinion the best chef on the planet. This made her perfect for feeding top quality meals to official visitors from Earth. It made a great impression on them, getting 5-star meals served in a colony situation on an alien world.

So eventually, when her second pregnancy made her work more cerebral in nature, Diane remembered this locked unit.

"Bob, I think it is about time we investigated the contents of that locked building in Metropolis."

"Locked building?" I repeated, wonderingly. "Oh, yes. The place you thought might be an armoury?"

"That's it. May I borrow your tame locksmith for the job?" This was a reference to Bert Johnston, an amateur locksmith who had been able to release the locks on the alien railway engine in Metropolis, and later on other trains.

"Bert? Now where is he at the moment? I have no idea. He was opening other locked trains some time back. Ask our Administration department about his current location, and availability. If he is free, you can borrow him, but I think you should have extra helpers on hand. Who knows what you might find in there."

Diane was unconcerned. "I can bring along a few of my armed forces group, ones that I can rely on. They should be able to deal with whatever we find."

"I am okay with that, but please ensure that you are all ready with your phones, so that you can update us as you proceed. Do you want a fire unit on standby, in case of any explosions?"

"I don't expect anything like that to happen, but it would be prudent to have them on call, darling."

"Right. Go ahead and fix them for your timetable of events. I might even come along myself, just to keep an eye on you."

"Only if you want to, Bob. I don't need you fussing over me: I am not THAT gravid!"

"Can I make a practical suggestion? Ask the Personalia to scan the building for heat signatures, noise emissions, and any other scans they care to do. The more data you have before you try the locks, the better."

"Now that IS a practical idea. I shall take you up on that. Will you be a dear and do the asking for me, Bob? I won't start on this investigation for a couple of days. I have to set up a few things in advance."

"All right. I'll get that request to them today, if you give me the exact location on the map of Metropolis."

Diane sighed at this civilian reaction. "Bob, you numbskull. It is already in your phone; you just have to dig it out. Here, let me show you." She located the digital map, found the building she wanted, highlighted it, and handed it back to me. She grimaced, "Men!"

I must have looked sheepish, but I refused to rise to the bait. "Thank you, dear." I set about the phone call.

The Personalia were back to me later the next day. "Governor, we have made various scans of that building from a Landership, with little to show for it. There is no discernable heat signature other than the normal pattern for a building in this city, and there are no sound emissions from it, just reflections of sound hitting it from elsewhere. We flew a Landership over it, and took an x-ray. Nothing showed up of value or interest. We are sorry to be reporting a set of zeroes, but it is still data. Our opinion is that the building has thick walls and roof, making it almost bomb-proof, for some reason."

"It is indeed data. Thank you for your help, anyway."

I reported the situation to Diane, who made a pouting smile with her lips, then kissed me lightly. "Well, you have to take it as it comes. No point in delaying any further. I lucked out with your locksmith pal: Bert is ready for tomorrow, if that suits you, Bob. I'd like to get this done before my second child arrives."

"And my fourth child, my lovely." I upstaged her. She laughed, waggling her forefinger in front of me in remonstration. "You have Ruth and Mary helping you with that score, young man!" I just kissed her. The "young man" quip was reference to the fact that I was several years younger than she was.

The whole squad was there, next day. Bert Johnston, Diane, four of her troops, each equipped with sidearm and a bicycle for individual transport, and a vehicle loaded with high-powered rifles, just in case; and me. I reminded them that the colony administration would like a continuous report of this action, in case of accidents; so everyone was to switch on their phone, and maintain an open link to someone in their hierarchy. Diane kept hers open to the Admin Department, and I kept mine open to the Personalia.

We soon reached the building, where Diane insisted on a walk round its perimeter, just in case there was anything new to see. There was no change, so she set up her overwatch position some distance away, in case of explosion or similar unwanted event.

Bert was shown the main door of the building, and he settled down to study the lock. He had warned us that he preferred to examine a new lock closely before he tried anything at all. We waited.

After ten minutes, he stood up, and reported over his phone, "Never seen one quite like that before, but I am guessing that it works in a similar way to some I have seen on Earth. I need to see its interior first." He brought out of his pocket an extremely thin flexible tube that he fitted to his phone, and switched on a light in his phone. He then managed to push the end of the tube inside the lock, and began flexing it around, inside. He explained his technique: "This gives me a three-dimensional view of the lock's interior. I could even connect my phone to a 3-D printer if we had one, and print out what we can see. This one is evident enough that I can see what I need to see, just with this." He gestured. When his scanning was complete, he got his phone screen to display the inside of the lock as it appeared to his phone.

He mumbled to himself and we could observe him making gestures with his fingers as if manipulating a lock pick, while he considered his next actions. He eventually made his decision: "Right. Time to make a start." He selected a specific lock pick, and started to fiddle with the insides of the door lock. There must have been tumblers, for we could hear them click as he engaged them. He looked over at Diane, and said into his phone, "Mrs Kempe; Governor; I have no idea whether there is a booby-trap connected to this lock, or what, but I would like to complete this at a remove, so if we all moved back about 20 or 30 metres, it would be wise. He revealed from his boiler suit a folding rod that connected to his lock pick and allowed him to operate it from a couple of metres distance. He could not get further back and still manipulate the pick, so that was his safety limit. We followed his advice, and shifted accordingly, leaving him to his fate.

Once everyone was in place, he delicately tripped the final tumbler inside the lock. It was a tense moment, but an anti-climax. Nothing happened. Bert motioned to everyone to stay as they were. "Mrs Kempe, I have to go forward and see if I can now swing open this door. There might be a motion sensor inside, or a bomb set to go off as it opens, that is why I want everyone still to remain way back. Another possibility is that there is a poison gas canister inside, which gets released when the door is opened in the wrong way."

After that, everyone was very happy to stay well away.

Bert went forward and tentatively pulled the door by its handle. Nothing moved. Next, he tried pushing. Nothing happened. Finally, he tried pulling the door to the side, and this worked. It slid smoothly to one side, into the frame of the building for a few inches, and Bert jumped away to one side in case he was faced with something undesirable. After a moment or two, he considered it safe to return, and this time he resumed pulling the door aside as far as it would go, keeping his body sheltered by the door as much as possible; his face protectively turned away from the entrance. This allowed the observers better views of the interior from the outside world. They looked at what was revealed.

There was an interior door displayed, with a large sign affixed to it, written in two different scripts. Not knowing the Braalian or Lubarian languages, or their styles of writing, this meant nothing to Diane and her team. She called to everyone: "Bert! We stop at this point, and wait. I need to get a translation of this sign. It may be a warning of what lies ahead, and we need to know urgently. Everyone please take a break."

She called to me: "Bob, ask the Personalia to translate the sign!" I walked forward towards the door, and when close enough, I pointed my phone's camera at the sign, and sent the picture to the Personalia, asking for a translation. Having developed close contacts with what we called the Newcomer civilization, the Personalia knew all their languages. The translation was not long in arriving, in the form of a duplicate image with the text changed to English. I read it to myself first.

It read: "City Archive. Do not enter without authorisation. Users must have a relevant city official with them at all times. Copying will be at the discretion of the official, and may only be copied once into a non-duplicable format. These records are vital to your city: treat them with respect."

I quickly copied the translation to Diane and Bert, for their information. Diane asked Bert to come back to her vantage point, for consultation. He came up close, and then he was quickly joined by me; I now had a proprietary interest in this archive, as Governor of the planet.

"Well, Mrs Kempe, what, if anything, do you want me to do now? Are you expecting any more locks?" said Bert. I looked at Diane for her decision. She nodded to Bert after a glance at me.

"Bert, there may be units inside which are locked. It is advisable to have you on hand, if you don't mind." He nodded his acquiescence. "Right."

I queried him, "Did you check for poisonous gases?" Bert looked down as he replied,

"No sir. I was assuming that if no-one showed any symptoms, the atmosphere would be normal."

Diane however accepted my point. "I think we should check that out. Have you any means of running such a test, Bert?"

"I can test for explosive mixtures, but I haven't anything that will say exactly which gases are present."

Diane dismissed this as of no consequence. "I have an app on my phone that analyses any gas sample. Take it and use it, Bert." He shamefacedly collected her phone after she showed him the way to operate the app. He went off to the building again. Diane put a hand on my arm. "Stay away for the moment, Bob. Just a precaution." She warned her team to remain in their positions.

Bert opened the inner door slightly, and stuck the phone through the crack, with the app activated. After about a minute, he pulled it back and examined the result. He eyes widened, and he walked swiftly back to Diane and myself. He spoke quietly to us.

"The reading shows that the building is filed with Argon gas. It is an inert gas, so that it will not react with any documents or other storage media."

Diane had an intake of breath, as she remembered something. "Bert, the U.S. National Archives stores its most valuable historical documents in cases filled with argon gas, for just that purpose. I remember a visit there, when it was explained to us. Argon is one of the inert gases, and the best one for this task. How do we enter to see anything? Do we have to wear spacesuits?"

Bert was apologetic. "I should have mentioned this before, but there is a button next to the door, and it has a label that meant nothing to me. I'll go back and take an image of it for you."

He did so, and brought his phone back. Bob copied it to his own phone, and again asked the Personalia for a translation. They told him: "Atmosphere change." Diane sent Bert back to press the button, then do the gas test every 5 minutes.

As a result, in ten minutes he was able to say that the atmosphere inside was now breathable. Diane sent her armed team to make a careful study of the interior, without touching anything; to take pictures of everything, and report back to her.

They accomplished that task very quickly, allowing us to examine the views of the interior. Inside were banks of presumably locked drawers against the back wall, except for one location where a machine stood, fixed on a table. Against the other walls were tables and chairs. On each table stood a similar machine. Above each machine, a section of blank wall surface was marked in a shape that made Diane suspect a built-in monitor screen. She called everyone together for a group discussion.