Sanghyuk watched as Yoohyeon rummaged through the papers lying on her desk as she carelessly threw them around, sending sheets of paper flying into the air. Even though he was most definitely not of this plane, he still put his hand up to shield his face from the onslaught of flying papers. 

"Uh...Yoohyeon?" he slowly asked. "Did you forget something?"

"I can't believe I seriously missed that!" she murmured to herself. "It was right in front of me!"

She shuffled around, looking through different case files mixed in with her homework, clearly not even paying any heed to the other leaning against the wall. Sanghyuk huffed, slightly offended at being ignored. 

So he was simply forced to resign himself and with a big sigh, let the back of his head hit the wall he was standing against since it didn't look like she'd be giving him any attention any time soon. 

She eventually pulled out a light beige file, pushing away all other papers and files off the desk, leaving them a crumpled mess on the floor. Sanghyuk crinkled his nose slightly at that, but went over when he saw her gesturing to him.

"Come over here," she said, the beige file in front of her.

"This..." he said as he recognized it. "Is this...?"

"Lee Jaehwan's autopsy report, yes."

"Why did you bring out the autopsy? Wasn't that the first thing you went through?" he questioned.

"I did," she nodded. "But I missed something extremely obvious."

Before he could as, she opened the file and held onto the edge of the desk for a quick moment. The opening page of the report was yellowed with age, an old black-and-white large sized photograph of Jaehwan beside the main report. 

She quickly scanned the paper report, handwritten in messy letters, given the absence of proper computers at the time. When she found a particular line, she ran her finger under the letters, murmuring the report before she finally stalled and pointed furiously.

"See that?" she told him. "I totally missed that!" 

He peered over her shoulder, narrowing his eyes at the letters. "...s...scent...vanilla scent discovered on body around victim's stab wound?" he read out. 

She nodded, a triumphant smile on her face. "What does a vanilla scent prove?" he wondered. "Some sort of oxidation? Perhaps some compound left behind by the true killer?" 

"You're close, but still so far, Sanghyuk," she told him.

She leaned over to her side, pulling out Taekwoon's diary she had obtained from the records at the asylum he'd been housed at. She flipped through the pages before settling on a certain one. 

"Taekwoon's thoughts have always been mixed, especially after the murder," she explained. "But there's always been one person popping up all the time, Kim Bora."

He hummed and nodded. "His girlfriend, no?" he wondered. "As far as we know, their relationship was rocky when the killing happened. She was most likely cheating on him with Jaehwan, wasn't she?" 

Yoohyeon nodded. "Exactly," she said. "However, despite everything going on in his mind, her memory seems to be clear to him. This diary shows that when he thought of her, his thoughts were clear, despite him suspecting that she didn't return his feelings."

He furrowed a brow. "So what does this have to do with the case? Are you getting off topic again?" 

She pointed to the page. "Read this," she urged him.

He shrugged. "If you say so," he sighed slightly. 

Great, even a ghost was beginning to lose faith in her.

He leaned closer to her in order to see the words on the diary clearly, suddenly bringing his face in much closer proximity to her. She drew a quick breath, before relaxing quickly as she realized that he was oblivious, turning away to hide the reddening on her cheeks. 

"Her scent always remains with me," Sanghyuk read out. "Her scent...that of vanilla-" He paused, his eyes wide, rereading the sentence. "He mentioned her scent..." he slowly said.

"Probably her perfume," Yoohyeon surmised. "According to this, it seems to be her signature scent. If you've read the diary, you'd have seen mentions about a vanilla scent at least three times before the entries lost coherence." 

"And the same scent was discovered on the victim's body, especially around the stab wound..." Sanghyuk held his chin. "Is this going where I think it's going...?"

She nodded. "We've been looking for a male murderer all this time," she told him. "That's been our fatal mistake." 

"Wait," Sanghyk held up his hand. "So...Jaehwan wasn't killed by a guy. He was killed by..."

"A girl," Yoohyeon said.

His eyes widened as he seemed to have reached an epiphany. "W-what you're suggesting is incredibly crazy, but it strangely fits!" he exclaimed. He turned to her. "But are you completely sure?"

She sighed deeply. "There's only one way to find out, isn't there?" she said. "If my deduction is true, then a chain will break."

She rushed back to the chamber with a file in hand, making the other ghosts seem worried about her.

As she quickly placed her files on the dry ground in front of Taekwoon's prison, she saw Hakyeon lightly nudge Sanghyuk and point to her.

"No, she's not crazy...yet." She was sure he added the last part on purpose. 

Ignoring him, she shuffled to her feet, grabbing the attention of the three ghosts and a very concerned Taekwoon. 

"Gentlemen, today is your lucky day," she proclaimed. 

They stayed silent. "I think I've made another breakthrough in the case," she said, her smile dropping softly.

She went back down to her knees so that she was eye level with Taekwoon. "I'm not happy with what I've found though, and I'm sure the four of you will be worse off if you hear this," she told him. 

He stared at her, dark eyes pained. "If there's one thing I've learnt over these years," she said, "it's that the truth is something that's often scarier than fiction. It has the potential to bring about justice, but it also has the potential to destroy lives." She narrowed her eyes at the chained prisoner. "Are you sure you want to hear the truth?" she questioned him. "Are you sure you can handle the truth?"

A slow minute passed as they held eye contact, not once during which either of them looked away. Eventually, Taekwoon nodded slowly.

She hummed. "Alright," she said, getting to her feet. 

"We haven't had concrete proof that Taekwoon is innocent, however, we're now sure that due to his sleep-walking, its impossible for Taekwoon to have committed the murder."

"The only way to prove otherwise was to find the actual killer, wasn't it?" Sanghyuk asked.

She nodded. "The evidence against Taekwoon is overwhelming. Not only was he found at the crime scene with the murder weapon in his hand, he also confessed in court. It's incredibly hard to overturn this as a confession is the best evidence one can have."

She took a deep breath. "However, that was because Taekwoon has believed himself to be the murderer all along."

She turned to Taekwoon, who was watching her intently. "You thought you were the murderer because you were at the house when you woke up, right? But you never gave thought to the other side, did you? That someone else might have visited the house before you? That the murder happened before you entered Jaehwan's house?"

Sanghyuk held his chin. "If Taekwoon was still sleep-walking when he entered Jaehwan's house, there's a big chance that the murderer took the chance to pin it on him after seeing his state." He looked up. "This leads to the deduction that whoever visited Lee Jaehwan before...was the one who killed him, and not Taekwoon."

She turned to Sanghyuk. "Forensics weren't as strong back then as they are now, were they?" she asked him. "It was harder to estimate time of death then of a corpse. If the killing happened close to Taekwoon's arrival, one might find it hard to accurately estimate a time of death." 

"So somehow, Taekwoon ended up at Jaehwan's house within a couple of hours after the murder?" Sanghyuk asked.

She shook her head. "In order to be properly framed, he would have had to show less than half an hour after the killing in order to be framed like that. Today, we might have been able to look at the body and found that the body was killed before Taekwoon's arrival, but back then they probably just assumed that he had killed him at that moment." 

"So now the question comes...who was with Jaehwan when he was murdered?" Sanghyuk offered. 

She nodded, turning to Taekwoon. "I read your diary," she told him. "A certain person always seemed to be popping up; your girlfriend, Kim Bora."

The ghosts stiffened visibly at hearing that. It seemed even Taekwoon's friends knew of her well.

"I never knew what role she played in this, seeming so connected to both you and Jaehwan. But then it hit me when I remembered a normally insignificant point in Jaehwan's autopsy. Vanilla scent."

Taekwoon's mouth dropped open. 

She picked up the autopsy file and flipped through it. "The scent was found all over the victim's body, though it was overpowered by body decay. It might have been completely erased had the police not arrived on time to apprehend Taekwoon and get an autopsy on the corpse. But...the scent was found to be especially a lot on the stab wound." She closed the file.

"Your girlfriend was with your rival when he was murdered," she slowly told Taekwoon before taking a deep breath.

"Hence, the one who must have killed Lee Jaehwan was Kim Bora!"

Silence fell over the entire chamber, only broken by a metallic crack as the bottom chain on Taekwoon's left hand snapped, followed by the sounds of rusted metal pieces falling to the floor.