By the time L returned to HQ, C had decided she'd been out for long enough and gave the reins back to Cassandra. The young woman suddenly swayed against L as they rode the elevator up to their room. He steadied her by the shoulders.

"Easy there. Deep breath."

"L-Lawliet?" Cassandra blinked in confusion. "What happened?"

"C and I returned to the hospital." When her eyes widened, he added, "No incidents this time."

She visibly relaxed, tension leaving her shoulders, and pulled the clip out of her hair. As her red hair tumbled down, L caught a whiff of orange blossom. He let one shoulder go and ran his fingers through Cassandra's hair as his hand trailed down to support her in the small of her back. So soft...
The elevator dinged, interrupting L's brief trance. He allowed Cassandra out first and then slumped behind her, all the while keeping his head down to hide the light pink color of his cheeks.

"So, um," Cassandra glanced behind, "why did you go to the hospital? Is everything all right?"

"Hm? Oh, yes." L fished their room key out of his pocket and opened the door. "We received a notification of another possible Kira-victim, so we went to the morgue to see if C was able to speak to the deceased."

"And... are you okay? I know you... don't do well in morgues."

That was putting it mildly. But L appreciated the softer phrasing nonetheless and nodded. "I'll be fine once I'm back behind the computer and focused on the task at hand."

"I take it C spoke to the person's ghost then?" asked Cassandra.

"She did."

L said nothing else, and Cassandra didn't ask. They agreed long ago the least she knew about C's ghostly encounters, the better. There was the matter of C's deal with the ghost to meet every Sunday, but she'd assured L it wouldn't be a problem. He trusted her to take charge when needed. Though Cassandra was the dominant personality, C had perfect control over their subconscious switching. Most of the time, anyway.

"I need to go back downstairs," said L. "Will you be all right until I come back this evening?"

"I'll be fine," answered Cassandra. "I'll... keep busy."

L followed her gaze as she looked around the room. It was the first time he became painfully aware of what little he had that wasn't decoration — and there was only the bare minimum of that. The book case only had four books, which Cassandra must've already read to pass the time. There was no TV, and the laptop was C's, which she kept password protected. He didn't even have a deck of cards to play solitaire. 

"Would you like to go shopping for some things?" L inquired. "Watari can drive you, and you can take Amane as well if you want company."

The flicker of panic in Cassandra's eyes betrayed she really didn't. "N-No, it's fine. I'm a bit tired, actually, so I'll just take a nap."

"Okay."

L walked back to the door as Cassandra threw back the cover from the kingsize bed. But he paused with a hand on the handle. The strangest sensation rolled over him. He felt... guilty. But why? For leaving Cassandra? No, that couldn't be it; he'd left plenty of times before. For not providing her with something to occupy herself with? He was a detective, not an entertainer. Then what was it?

"Lawliet? Is something wrong?"

L glimpsed behind and gasped lightly. His heart lurched at the sight of Cassandra standing at the foot of the bed. She'd thrown the black pencil skirt and white blouse over the couch and had been on her way to the bathroom to get her nightshirt when she'd noticed him standing on the threshold. She always looked so fragile, wearing oversized clothing and hiding behind a curtain of hair. Yet now, with nothing on her body except her underwear and a cream top, she radiated a feminity L was unaccustomed to. It stirred him.

"Lawliet?"

Cassandra's worried voice pulled L from his stupor. Before either of them realized what was happening, he'd crossed the room and taken Cassandra by her hips to press her against him. She squealed in surprise and held him back with her hands against his chest before their mouths could touch. L met her alarmed gaze but didn't release her.
She felt so warm, so good, so soothing... Not for the first time since meeting Cassandra did L imagine what would happen if he just gave in to the heat rising inside of him. To the quaint yearning that seemed to cause his brain to hit pause and reset. Try as he may, even the great L couldn't ignore the obvious clues his body was giving him. But...

"I'm sorry."

He ran. Away from the room, away from a dumbstruck Cassandra, away from the fantasy, and into the elevator. L furiously punched the button to the main office and leaned forward, arm stretched and supporting his weight.
His heart raced inside his chest. His breath came out in ragged puffs as he struggled to regain his senses before facing the others. He hated himself for being so weak. He hated C for berating him about Cassandra. Most of all, he hated Mercy.
As long as she lurked in the darkness, it could never happen. They could never happen. Never.

📓💀📓

Light checked the time at the bottom of his screen for the umpteenth time. L and C left two hours ago and should've been back by now. None of the inspectors had an alert from the hospital, so he was fairly certain nothing bad had happened this time. But then where the heck were they? 
His father yawned beside him and shook his head to stay alert. Light pitied him. Soichiro Yagami had always seemed a giant in his eyes, but these last few months had made him far too human. His black hair had grayed, he'd lost weight, and we grew tired a lot faster than before. Being away from the comfort of home and the loving company of his wife and daughter weighed heavily on him. Not to mention he was still recovering from a heart attack. The added strain of the investigation and of his son still being suspected of being a mass-serial killer weren't doing him any favors, either.

"Dad, you should rest," said Light.

"I'm fine, son," said his father, waving his concern away. 

"No, you're not; you're practically falling asleep on your chair."

"He's right, Chief," said Matsuda. "You're looking a little pale."

"I just need some coffee. Get me a fresh cup, will you?"

Light hurriedly mouthed a clear 'no' to Matsuda before putting a hand on his father's shoulder. "Come on, Dad. Let's go up so you can rest for a bit. I can take the laptop with me to keep working in our room. It's just running and matching statistics, anyway."

Soichiro sighed and took off his glasses. "Maybe you're right. Just an hour, though."

"Sure. Now come on. Matsuda, will you inform Ryuzaki when he gets back?"

"Of course," said the young inspector. 

Light nodded gratefully and helped his father up. When they passed the open staircase, he caught an agitated yet hushed voice coming from above. 

"L, please, act before it's too late."

Watari... and L? He's back already? Then why didn't he come sooner?

"Dad, you call the elevator," said Light. "I wanna refill my water bottle before we go to the room."

Soichiro waved absent-mindedly and continued to the elevator. The chain linking Light to his father was just long enough to allow him to go to the refreshment table and overhear the argument without raising any immediate suspicion. 

"People die every day," said L with his usual monotony. "Sometimes a death is just a death, no foul play involved."

Light glanced up at those words. Were they talking about that potential Kira-victim? Did it turn out to be a bust?

"You're really going to ignore this?" demanded Watari.

"No, of course not. But neither am I going to stir unwarranted panic."

"Unwarranted? There's nothing unwarranted about fearing that murderess may be on the loose again."

Murderess? What the hell are they talking about? 

"L, please," urged Watari. "You promised me you would take action at the slightest hint of trouble. C lost control at the hospital, and with what I learned happened on her flight over... You have no choice."

Light set down his water bottle after having filled it ever so slowly and reached for the coffeepot to prolong his reason for staying at the table. It shook in his hand. He strained his ears to listen to the rest of the conversation.

"The events are unrelated," said L firmly, "and you have no proof whatsoever that she was responsible for the man's death. I am well aware I promised to take action, but I see no need for it as of yet."

"L —"

"Watari, I will not repeat myself. Now please procure the items I mentioned before and leave them outside the door of our room. I don't want you to disturb her."

Light didn't linger to hear Watari's reply. He grabbed his water bottle and the cup of coffee and hastened to the elevator just as L sauntered down the stairs. He greeted Mogi and Aizawa — who'd just returned from their break — before nudging his father inside. Only when the elevator reached their floor and he entered the safety of his room did Light relax. Although, safety...

Where was that camera's blind spot again? Ah, right.

Light sat on the left-side of the bed with his laptop on his lap. Usually, his father would sleep left, but the man was so tired, he made no comment and instantly fell asleep on the other side. For a moment, Light considered covering him with the duvet, but it didn't appear his father was cold, so he left him be. Best not to disturb him.
Confident none of the cameras in the room could pick up his screen from his current position, Light pulled up the file he'd made on C and Cassia, as well as the NPA database. He'd hacked his father's password years ago, so he had everything he needed at the tip of of his fingers.

All right, the first thing I need to add to the file is the possibility C or Cassia may yet have a relationship with L after all. He said 'our room', not 'her room'. Even though it's so unlikely considering L's character, I can't ignore that detail. If those two are involved somehow, he's jeopardizing the entire Kira-investigation.

Light typed the info into his encrypted file and then leaned back against the headboard, making sure his facial expressions wouldn't betray anything. No doubt L would be watching.

Watari mentioned something happening on C's flight to Japan. A man dying. He sounded genuinely concerned about that. Terrified, even. 

His fingers flew over the keys again, summing up all the variables he needed to consider if he had any hope of discovering what happened on the plane. Surely it couldn't have been a possession like the one he'd witnessed in the hospital. There would've been mass-panic on the entire aircraft had a passenger been noted to suddenly have vine-like tendrils on their arms and legs, and claws instead of nails. But something had still happened, and he was determined to find out what it was.

Let's see now. C arrived here on July 23, and I know from Misa she met L during a case in London a few years ago. Assuming she still lives in the UK, I need to research incidents on all English flights to Japan in a time span of... twenty-four hours. No, wait, better make it forty-eight. Most of those flights leave England at night and arrive here then as well. It was the afternoon when she got here, so I need to consider she could've stayed at an airport hotel upon arrival.  

Light stopped typing. He cursed silently, hissing between his teeth. He'd almost forgotten about the train from London to the European mainland. C could've taken the train to another country to depart from there. He recalled Paris had a large international airport, as did Amsterdam. That changed his variables considerably. 

Dammit, this is going to be a lot more complicated than I thought. Both C and L are cunning detectives who know how to stay under the radar. Traveling incognito via different airport, and even under false identities, wouldn't be a problem for them. I need to broaden my search, but I also need to know under what name C was traveling. Even if I had the passenger lists, those would be useless unless I had a face to match the name with. 

Suddenly, Light recalled border security scanned all passports from incoming travelers. C would've had to give something to them in order to enter Japan. And since the latest anti-terror and safety project, certain high-ranking individuals within the NPA also had access to that data.
Light shot his sleeping father a grateful look and set to work again. Not wanting to rely on the assumption C came from England, or any other European airport, he widened his search to all flights in a seventy-two-hour window to July 23. He entered C's physical descriptions manually, as he didn't have a picture to input and compare with, and... froze completely a mere inch above the enter key. Almost too late had he realized a description of C would be completely useless if she'd donned a disguise. 

She could have, thought Light in dismay. C would've done everything she could to stay under the radar, including change her appearance. Hair-dye, a wig, glasses, contact lenses, even heavy make-up... Dammit!

He slumped down, dragging his hands over his face. What was he supposed to do now? Literally go over every single woman that went through customs in the hopes he might recognize her? Narita Airport had hundreds of incoming international flights per day. And what if she even didn't come in through Narita at all?

There has to be a way I can track her movements. I can't let this deter me. Watari isn't happy C is here, and dammit, I'm gonna find out why! Okay, come on, Light, think. If you can't solve the puzzle from one angle, find another. The dead man would've been taken to the morgue, so let's go with that. 

With newfound determination, Light pulled up the morgue database to check all entries around July 23. Fortunately for him, he quickly found what he was looking for. He opened the report for one Toriyama Nakamita and frowned at the information. The seventy-three-year-old man had died from heart failure, suspected to have been caused by Takotsubo, as per information provided by a friend.
Light sat back. This wasn't what he'd expected. Takotsubo — more commonly known as Broken Heart Syndrome — was often brought on by stressful situations and extreme emotions, and was usually temporary, given proper medication and support. It could, however, also lead to serious heart problems. But how could C have anything to do with this death? Light checked again to make sure he had the right file, but Mr. Nakamita was the only one who came in from the airport that week. It had to be him.

At least I have the flight information now. I'll only have to check one passenger manifest instead of thousands, thank God. 

Light quickly copy pasted the details to his encrypted file. He was about to close the morgue database when an entry from two days ago caught his eye. He squinted at the picture, imagining puss-drenched dressings covering half the woman's face and her head bald instead of with shoulder-length black hair, and gasped as he recognized the burn victim from the hospital. 
Curiosity taking the better of him, Light clicked open the report. He scanned the coroner's findings and was left stumped for a second time in just a few minutes. Hurriedly, Light took Mr. Nakamita's information beside the woman's. His eyes widened.

It's the same. Both died at a minute to midnight in the time zone they were currently in. And both causes of death can be traced back to Broken Heart Syndrome. 

Light read the additional notes in the reports. Mr. Nakamita had lost his wife, son, daughter-in-law and baby grandson in a terrible car accident three months ago and hadn't been coping with the loss. And the woman, Mrs. Kishimoto, lost her husband and twin daughters in a fire, believed to have been started by the husband. 

These people lost everything, including the will to live. Is it any wonder their bodies gave out after their hearts already did? But this still makes little sense. Two cases of BHS in less than a week and coming into the same morgue... What are the odds of that happening?

It was yet another question to plague Light Yagami from then on. Yet another reason for him to learn more about C and the potential danger she truly was.