It had been a week since our insightful visit to Dr Stone, and my lounge floor was littered with Tobi's sketches.

The blond Katki had spent any spare time he'd had between trips to Rannik drawing pictures of the inside of the Kinnisvara, at my request. This would be my way of seeing what lay inside the elusive estate that was usually hidden from view behind the foreboding outer walls.

Tobi had created numerous scenes from various angles, and our job this morning was to piece them together like a giant jigsaw puzzle.

Imposing buildings fringed with tall pillars, stunning fountains, stone statues of varying shapes and sizes, a dense orchard and pretty flower gardens were all captured in impeccable detail on the paper we'd bought from Linn.

As we fitted the drawings together, using Tobi's exclusive knowledge, we were able to build a map of the different locations he'd depicted.

"There," I said, cocking my head to one side as I studied one of the sketches he'd made of the gardens. "What's that you've drawn behind those rose bushes?"

"I don't know," he admitted. "But I've been closer to it than this, so I can draw it bigger if you like?"

"It might be nothing," I replied. "But if I can see what it is in more detail, I think it might be helpful so that I can be sure. How about I make lunch while you work your magic?"

After Tobi nodded his agreement, I cupped his chin, kissed him gently on the lips and set about making some pea and ham soup with crusty bread, inspecting his latest creation after we'd finished eating.

Now that I could see it more clearly, the illustration appeared to portray a copper pipe.

"This rose garden," I said as I looked at the relative locations of everything. "It's close to the river, I think?"

"Yes, just here," Tobi acknowledged by pointing to the position on our crude map that coincided with where I believed it to be.

"This pipe looks as though it connects to the river," I mused as I picked up another illustration that also appeared to have a section of pipe in the background. "And it looks like there's a second pipe in this drawing," I added as I moved along the sketches towards the river. "Can you tell me where each of them lead?"

"I think so," my companion nodded. "That second one you pointed out follows the edge of the orchard, round past the central living area." Tobi pointed to the collection of buildings on the map we'd made. "And that one that you could see behind the rose garden? It disappears through the exterior wall over here," he added, gesticulating towards one of the outer edges of the estate.

"Near the science labs," I mused. "Which is where it makes most sense for them to be producing the synthetic progesterone. No doubt the other pipe is taking water from the River Vesi to the Kinnisvara for the residents to drink before it gets contaminated."

"I can see the logic," said Tobi, nodding. "But having this information and being able to do something with it are two entirely different things."

"You're right," I agreed. "Which means that in order to stop these chemicals getting into the river, we either have to stop the supply at their source, or somewhere en route."

"Given where you work, maybe you could stop it ever entering the pipes?" suggested Tobi hopefully.

"Not without someone noticing," I repudiated reluctantly as I gave the idea some thought. "And even if I could do something covertly, the system wouldn't be out of action for long enough. Their procedure needs to be defective for a few weeks before it will have a significant enough impact, and those that work in the labs are likely to do regular safeguarding checks. For any kind of sabotage to work, we need those that are adding the progesterone to believe the hormones are still entering the civilian water supply. Which means that actually, the best way to tackle this is to remove it here, once it's already in the pipe," I added, indicating the portion of the pipe that ran alongside the rose garden.

"The Kinnisvara is heavily guarded," Tobi pointed out dejectedly. "We certainly won't be able to sneak past the sentries, and they're too well trained for us to be able to fight them."

"There has to be a way that we can get inside these walls," I declared, although I suspect I sounded more confident than I felt.

"Maybe we don't have to," the platinum blond said slowly, seemingly pondering the options. "Surely it only needs one of us to get inside and mess up their system?"

Turning to face him, I saw him start to grin broadly, and I immediately understood which one of us he was contemplating should go inside.

"You can't seriously be considering going in on your own?" I insisted.

"Why don't you hear me out," he stated calmly. "And if you still don't feel comfortable with my suggestion, we'll look at other options?"

I paused for a moment to digest what he'd just said. That seemed reasonable, and I nodded.

"All right," I agreed. "What is it you're thinking about doing?"

"What I do best," he smiled. "Being Katki."

Tobi and I spent any spare time we had over the following week rehearsing our new act. Within the first few days of doing so, we told Seren and Peter about our intended strategy for infiltrating the Kinnisvara. Their first reaction was that they thought we were taking too many risks. After some discussion, we decided to show them our performance. Seeing us in action seemed to alleviate most of their concerns, agreeing that Tobi and I were very convincing. Peter even offered to lend us his wedding ring in the hope that it might add an extra layer of authenticity to our plan. I was concerned about the possibility of us losing such a sentimental piece of jewellery, but he just smiled and stated that he had confidence in us and wanted to help our charade to be as believable as possible.

We showered and dressed early that Saturday morning, with Tobi donning his brown uniform and displaying his tattoo so that he was intentionally looking every bit like a Katki.

After breakfast, we set about preparing for the day ahead by securely fastening what Tobi would need for sabotaging our target to his calves. The traditional Katki outfit would be able to hide what he needed underneath, so we planned to use it to cover the felonious implements.

Earlier in the week, while in the laboratory, I'd covertly created a chemical compound that would weaken the copper pipe. While I knew that copper was a relatively soft metal, I also knew that Tobi didn't have as much brute strength as either myself or Peter, and I wanted to give him the best possible chance to damage the pipe such that it would prevent further contamination of the civilian water supply. By sending him inside with a chemical spray that would weaken the atomic bonds of the conduit first, I knew the metal would require much less effort to fracture and split open.

And so, after securing the chemical spray to one of Tobi's calves and a thin but very sharp blade in its sheath to the other, we covered them up with the Katki uniform, ensuring he looked innocuous.

"Ready?" I asked as we were about to leave to catch the transport bus to the Mart.

"I am," replied Tobi, his features devoid of emotion and his poise formal.

I slapped his arm playfully.

"Save it for when we're on the move," I chuckled at his premature enactment.

"Just getting into the right mood," he told me with a smile.

"Feeling confident, then?" I surmised.

"As much as I'm going to be," Tobi replied, a little more anxiously this time. "Just hoping nothing goes wrong. You?"

"Same," I concurred. "We should be fine. We've practiced plenty. You have Peter's wedding ring, right?"

"In my back pocket," he nodded.

"Then let's go."

Upon stepping out into the pleasant spring morning, we were greeted with the sounds of birdsong and the scent of cherry blossom. It wasn't long before we arrived at the Mart on the transport bus and were walking through the bustling streets towards the Kinnisvara, with Tobi adeptly playing his role throughout. I missed being able to interact with him as I normally would, but we couldn't risk exposure.

The winding roads took us uphill towards our goal, and after a short ascent, Tobi and I were approaching the extravagant main entrance to the home of the Andekas. I'd never been this close to the ornately carved oak gates before. The formidable barriers were closed and guarded by several sentries dressed in orange and black unforms who each carried some kind of weapon that I was unfamiliar with. Flags rippled in the light breeze on either side of the access point, proudly displaying the fertility symbol that we now knew to be disingenuous, and I winced internally at the message being sent by the innocuous looking propaganda.

One of the burlier guards approached me and spoke in a formal tone.

"State your business."

I composed myself quickly, noticing that the man's deep brown eyes were at a slightly higher level than my own, which given my height, didn't happen to me often.

"Good morning," I greeted him. "My wife and I have been granted the honour of being blessed with a child and were recently invited to the Kinnisvara to conceive. Unfortunately, I've managed to return home having misplaced my wedding ring. The last place I remember seeing it was in a rose garden near the river. With it being so sentimental, I hoped one of you might escort me inside so that I can retrieve it?"

Seren had already informed me that the sentries were not permitted to leave their posts for such fripperies, so I already knew what the answer would be before I'd even asked the question.

"I'm afraid we cannot allow that, sir," the guard responded kindly, his brown eyes softening slightly as he spoke.

I suspected that part of the reason for his change in demeanour was because he'd noticed Tobi. The 'ownership' of a Katki, combined with the fabricated story of my pregnant wife was evidently helping him to draw the conclusions I wanted him to draw – that I'd been recognised by the Andekas for my loyal services.

"I understand," I responded dejectedly, looking downward towards his hand, since what I saw there would determine my next course of action. "I see you're also married," I surmised when I saw the gold band on his finger. "I suspect your wife would be more understanding than mine if you lost your ring."

"Unlikely," he responded with a hint of empathy in his tone. "I'd be in the doghouse for weeks. Maybe even months."

"Yeah, I doubt mine will calm down any time soon," I sighed.

"You seem like a decent man," he offered sympathetically. "And I wish there were something I could do, but I can't let unauthorised civilians inside. I'm sorry."

"Don't be," I assured him. "You have your job to do. It seems I was being overly optimistic. Thank you for your time."

Turning to Tobi, I instructed him to follow me, and started walking away from the Kinnisvara with my Katki in tow.

After a few steps, I ordered the platinum blond to stop, then turned back to face the sentry.

Pretending I'd just had an epiphany, I led Tobi back to the gates.

"What about a Katki?" I asked the guard enthusiastically.

His deep brown eyes stared back at me in confusion.

"You just told me civilians weren't allowed inside the walls," I continued. "What about a Katki? I could give you complete control of this one, so that it wouldn't even be me that issued the instructions," I suggested with a hopeful tone.

The sentry seemed to consider my request carefully, turning his gaze to Tobi, who stood stolid and motionless next to me.

"Does it know what to look for?" the other man asked sceptically.

"I don't know – you could maybe show it your one?" I suggested, ensuring I matched the pronouns that the guard used. "What's your name, sir?"

"Saul," replied the brown-eyed man, still looking a little bewildered.

"Seven Zero Eight One," I addressed my Katki. "For the next ten minutes, I want you to follow Saul's instructions as if they're mine. Do you understand?"

"I do," he replied indifferently.

"Will you comply?" I verified.

"I will."

"So, now you can give it any instructions you want to," I confirmed brightly, my eyes refocusing on Saul, hoping he'd take the bait. "And if you instruct it to follow me home, then we'll leave without another word."

Minutes ticked by as I waited anxiously for Saul's reaction, wondering whether we'd done enough to convince him with our performance. After what seemed like forever, the sentry made his decision.

"Seven Zero Eight One," he started tentatively, reading the numbers aloud from Tobi's neck. His brown eyes drifted towards me hesitantly, but when I said nothing, he returned his focus to Tobi, holding out his hand with the gold band on it. "Your custodian has lost a wedding ring that resembles this one in the rose garden of the Kinnisvara near the River Vesi. Do you know the garden I'm talking about?"

"I do," Tobi replied, looking impassively at what he was being shown.

"I'm going to give you one hour to find the ring," Saul continued, a little more assertively this time. "While inside the walls of the Kinnisvara you must do nothing except make every effort to retrieve the item. If you locate it before your time is up, return with it immediately. If you're unable to find it within an hour, you must return without it. Do you understand?"

"I do," Tobi stated evenly.

Turning to face one of the other guards, Saul gave a solitary nod before returning his gaze to my companion as the second sentry disappeared from our view. A few seconds later, the imposing gate started to rumble open slowly.

"You have an hour," Saul informed Tobi, gesticulating towards the gap that had just been created. "Go."