Mission in another world with my transformed best friend

Watching Martha's smiling, enthusiastic, and slightly excited expression, Wang Kai noticed the ring on her right ring finger. The previous "misunderstanding" came to mind, and he quickly tried to explain it to her.

"Brother Kyle, you've been soaking for so long. A massage will help relieve your fatigue even more. Come lie down here. I'll apply some essential oil first, and then use the massage techniques I've learned to make you feel comfortable..."

"Huh? You're just coming up like this? I'm not wearing any clothes, no way."

“Why not? We’re family, aren’t we…”

"That's not the issue. Even though we're family, there's a distinction between men and women among family members. Besides... when you came here, did Alice say anything?"

Martha made a hushed gesture.

"Shh~ Last time I was too conspicuous and Sister Lan blocked me, but this time I secretly followed your scent behind your back..."

“Even so…” Wang Kai said, both amused and exasperated, “but that’s not the point. Martha, do you even know what ‘serving a bath’ means?”

Martha smiled slightly after hearing this, her face flushed even more, and her big eyes were filled with a kind of longing expectation. She stuck out her little tongue and replied.

"I wasn't quite sure before, but that maid just came over and explained it to me personally... And now, not long ago, you gave her a ring and put it on her finger. As her future wife, what's wrong with using 'bathing' to relieve her future husband's fatigue? Even though it's her first time, I promise I won't hurt you."

If the bathhouse hadn't been so quiet, Wang Kai would never have believed that these hormone-fueled words could come so casually from the girl in front of him. No, no, something must be wrong. That's it, the ring, it must be this.

Wang Kai seized the opportunity, mustered his courage, shook his head, and said.

"Well... I've actually been looking for an opportunity to explain to you that the ring I gave you is actually a 'tool' for our adventure team... it doesn't have any other meaning."

Martha simply blinked, then raised her right hand, glanced at the ring, and her smile became alluring.

"Brother Kyle, you're such a joker. The ring was supposed to be a 'prop' for the proposal. And later, you were the one who put the ring on my finger at my request, right? After we promised to become 'family,' you proposed to me. I was already prepared for this, but I didn't expect happiness to come so quickly. Now I feel so hot, and my heart is pounding. What should I do? What should I do?"

Things seem to be getting out of control. Judging from her words and even her body language, Martha's condition is heading in a "bad" direction. The redness on her face, hands, and feet is becoming increasingly noticeable. Could it really just be due to the high temperature in the bathhouse?

Although Wang Kai has been single for almost thirty years, he's certainly seen it all, even if he hasn't experienced it firsthand. His tone, tinged with embarrassment, and his expression have absolutely nothing to do with regulating his skin temperature. To put it bluntly, it's a direct manifestation of his rationality being completely driven by his emotions.

Martha is young, but she is quite mature for her age. Rather than saying that her somewhat coy and flirtatious language is a true expression of her inner thoughts, it is just that because she is inexperienced, even she does not know what she is saying.

Wang Kai was all too familiar with this struggle between reason and emotion; it was exactly the same situation he experienced last night when he rambled on in a fit of rage, causing his popularity to plummet and leading to him being kicked out by Zhang Lan…

However, Martha seemed to have learned some "extra" knowledge from the maid. She slowly brought the hand with the ring to her mouth, and gently licked the magic stone on the ring with her tongue. The magic stone shimmered with resonant white light under the fluctuations of magic, and the ring on Wang Kai's finger blinked as if in response. The light shining through the steam and mist had a hazy beauty...

Having inherited the body of a passionate young man, one would expect that Wang Kai's rationality would have wavered long ago in the face of such a direct action from a girl. However, he did the opposite, his rational rhythm remaining intact, and he calmly replied.

"I'm sorry, Martha, a series of misunderstandings have led to you acting a bit strangely right now. Also, let's put the 'bathing service' thing aside for now. If you can calm down, I can continue to explain to you..."

"Sure, I'd like to get a little closer and listen carefully to Kyle's explanation, word by word, okay?"

The response grew louder as it approached. Martha bent down, crawling on all fours like a puppy towards the bathtub, her face flushed and her breath ragged, her hormones raging. Just before she was about to press against Wang Kai's back, she whispered something in his ear.

"Let him explain first. I made a decision that I would never take Sister Lan's place, and I would only secretly observe Brother Kyle or just smell his scent. But these past few days have been during her 'that' special period, and the above methods are no longer effective... And now, there are only the two of us in the whole bathhouse, and you are her future husband. Thinking about this, I can't hold back anymore."

As the sweet scent of the girl brushed against his earlobe, Wang Kai's wall of rationality finally came under heavy attack. He knew that Martha had beastman blood, and that the bloodline of beastmen, through procreation, would cause specific psychological changes at certain regular periods.

Simply put, these "demi-humans," like certain small animals, prioritize reproduction for a specific period, resulting in extremely direct and primitive behavior. This is one of the reasons why "demi-humans" suffer from discrimination...

Faced with this "traditional" setting, much like how pet cats and dogs sometimes get restless and irritable for a few days each month, owners usually just tolerate it. But now Wang Kai is facing such a direct expression from a young girl, and she's even setting aside all girlish reserve, revealing the innocent, cute, and naive Masha.

Previously, Wang Kai saw her as a younger sister, but now he has to accept the fact that she is a "woman." If he doesn't take action soon, judging from her rapid breathing, it will be a matter of minutes before he translates his words into actions...

"Little sister Martha, please calm down and listen to me, okay?"

"Okay, but I prefer to lie in your arms and look at your face while listening..."

"I'm sorry, I can't do that. If your sister Lan finds out, you'll have another 'sister'..."

"Another 'older sister'? I don't understand. Could you explain it to me in detail?"

As the voice grew closer, Masha slowly crawled into the bathtub, bringing her face close to Wang Kai's and gradually filling his vision.

The petite girl, her eyes brimming with longing and a mixture of warmth and sensuality, gazed at them from close range.

Wang Kai could no longer contain his racing heart. If it were Masha three months ago, he might not have had so many thoughts. But now, her tone and expression, as well as her suddenly rapidly growing body, all exuded a "masculine charm." The saying "a girl changes drastically at eighteen" might be true, but such a rapid change still caught him, her "older brother," somewhat off guard.