Chapter One: The Opening of Pandora's Box

Kai and Krystal sat side by side on the train, their tired expressions mirrored in each other's eyes. They are on their way home, after a very tiring day. Krystal had just finished her dialysissession, a routine that the siblings had become all familiar with. Krystal's chronic kidney diseases has taken a toll on both her physical and emotional well-being. But there was a hope on the horizon - a kidney transplant was schedule for next month.

As the train sped through the next station, Kai's thoughts drifted back to their difficult past. They had lost their parent's at a very young age, leaving them orphaned and valuable. Their Aunt from their mother side had stepped in to care for Krystal, while Kai took on the role of a security officer in the Presidential Security Group, responsible for protecting the President of South Marquina.

Kai's dedication to his work was fueled by the desire to provide a better life for his sister, and at the same time, he also knew the importance of keeping their President safe, as the stability of the country meant a brighter future  for his sister, for the citizens in their country, and for him. It wasn't an easy job but the sense of purpose it gave him helped him push through the long hours and constant vigilance.

Krystal moved a bit, and it was a signal that she is finally awake from her quick nap. Kai gently patted his sister's head, offering a silent reassurance that he is always there for her.

"How are you feeling, Krystal? Are you hungry after today's dialysis session?" Kai gently asked his sister.

"I'm actually exhausted, Kai. But I need to hang in there because I can finally get a kidney transplant. I can't wait for the surgery so that I can live a normal life." answered Krystal.

"I know, Krystal. It hasn't been easy for you, but you've been so strong, and I'm so proud of you. Auntie Cecile is taking good care of you right?" Kai inquired

"Yes, Aunt Cecile is amazing. I'm grateful to have her care and support. And I'm grateful for you too, Kai. Working as a security officer must be tough, but you've always been there for me since Dad and Mom passed away." Krystal smiles in return.

"Of course, I'll always be there for you, no matter what. You and Aunt Cecile are the only family I have. And protecting our country's President is not just a job for me, but it's a way to ensure a better future for us. We've been through so much, and I want to give you the best life possible." Kai spoke again.

Krystal nodded in agreement, after she heard her older brother.

"I appreciate everything you do, Kai. We've faced so many challenges, but we've never lost hope. I believe that better days are ahead of us, especially with the transplant coming up."

Kai smiles in return, as he is feeling happy because he can finally see his sister looking forward for the next chapter of her life, and it was really obvious that he is willing to fight for her life.

"Yes. We've come this far, and we'll keep pushing forward. We'll get through this together and soon enough, you'll have a new kidney and a chance at a healthier life."

As the train continued its journey, Kai and Krystal held to hope, knowing that their bond as siblings and their resilience would carry them through whatever challenges lay ahead.

The siblings are now talking and making plans on what to eat for dinner later. It had been a long day for both of them, and they were looking forward to a warm and comforting meal with Aunt Cecile. 

"So, what do you feel like having for dinner tonight, Krystal?" Kai inquired to his sister.

"Hmm, how about some Chinese cuisine? It's been a while since we've had Chinese food. What do you think?" Krystal asked in return.

"Chinese takeout sound great! There's a new Chinese restaurant near our apartment that I've been wanting to try. I heard they really have good reviews." Kai smilingly suggested.

"Alright, it's Chinese food tonight!" Krystal chirped, while grinning from ear to ear.

As they scrolled through their favorite food delivery app, Kai's attention was suddenly drawn to the other passengers in the train. Many of them were coughing and sneezing, their tired expressions reflecting signs of illness.

A sense of unease washed over Kai as he observed the growing number of sick passengers. His instincts told him that this wasn't just a typical winter cold or flu. However, he didn't want to alarm Krystal, as he doesn't want to cause any panic to his sister. Instead, he decided to keep his observations to himself and try to protect his sister from any infections, because Krystal in her vulnerable state, and her immune system is a little bit down.

"Krystal, I think you should wear your mask. You know, just to be on the safe side." suggested Kai, in a nonchalant manner.

Krystal looked up from her phone, a hint of confusion in her eyes.

"Why? Is there is something wrong?" 

Kai shrugged, trying to downplay the situation.

"Well, it's not really that serious but I noticed a lot of people on the train coughing and sneezing. This is just a precaution, and it's better safe than sorry, right?" 

Krystal nodded, agreeing with her brother. She reached into her bag and pulled out two face masks, handing one to Kai. The siblings both put their masks on, then afterwards, they continued their conversation about their dinner plans. Kai is secretly keeping a watchful eye on the other passengers. He noticed that some of them looked visibly unwell. He silently hoped that it was nothing serious, but his gut feeling is telling him otherwise.

Kai remained alert, keeping a close watch to the passengers around them. He hoped that his gut feeling was wrong and that it was just the usual winter cold and flu, but deep inside him, he knew that he has to stay vigilant and protect his sister, no matter what...