In a moment of quiet in his apartment, Hong is startled by a shattered voice:

Hong: "What's that noise? Am I under attack?"

He rushes to the window to see shadows moving in the darkness.

Hong: "Who's there? Show yourself!"

An unknown voice echoes across the street:

Stranger: "Have you ever thought about your deceased friend's past?"

Hong closes the window in shock.

Hong: "How do they know? Isn't all that buried in the past?"

The next day, while investigating at the company:

Detective: "Do you have any enemies?"

Hong: "No, I can't imagine anyone hating me that much."

In a moment of silence between them:

Detective: "Perhaps you have enemies you haven't discovered yet."

Suddenly, a mysterious image appears on Hong's screen.

Image: "You know what happened that day!"

Hong: "Who are you? What do you want?"

Hong manages to get rid of the image after a disturbing conversation.

Hong: "I have to understand; I can't give up. I'll unravel these threads myself!"

While searching his apartment for clues:

Hong: "There must be something I missed. Maybe in my deceased friend's room."

He finds an old box at the bottom of the closet.

Hong: "What's this? I didn't know it was here."

He opens the box to find old notes and photographs.

Hong: "Perhaps this is the key to understanding what happened."

He falls into deep contemplation about the contents of the notes:

Hong: "My friend didn't talk much about his past. Perhaps there were secrets he was hiding."

In a phone conversation with his deceased friend's lawyer:

Lawyer: "There's a complex history behind him; he wasn't as he seemed."

Hong looks into the distance after receiving this news.

Hong: "I wonder if it's true. Do the coming days hide more mysteries?"

He feels sadness and confusion amidst unraveling the threads of the dark past.

While investigating his friend's past:

Hong: "He never truly trusted anyone. Perhaps he was hiding a lot even from me."

Hong confronts his friend's acquaintances at a café:

Friend of his friend: "We didn't know much about his personal life, but he was silently suffering."

Hong searches for signs of betrayal and suspicions in relationships:

Hong: "Maybe there are those plotting to strike at me through those I love."

In a moment of conversation with a colleague:

Colleague: "Do you know you're in danger? You must be careful."

Hong looks with anticipation and concern.

Hong: "Why do they want to harm me? Was my friend living in a world of lies?"

In a moment of breakdown:

Hong: "There seems to be no end to this puzzle. I feel trapped in an endless web of mysteries."