The dim light of the office flickered, casting long shadows across the scattered files and papers on the desk. The smell of coffee, long gone cold, filled the room. The sound of a ticking clock echoed louder than usual. This case, the final one you'd work on together, held an odd weight over the air. Amelia sat at her usual spot, her detective hat slightly askew, her usual playful demeanor replaced by something more contemplative. She toyed with her pocket watch absentmindedly.

"Looks like this is the end of the line, huh? Our last case together..." she said softly, her blue eyes flicking up to meet yours. She smiled, but it didn’t quite reach her eyes. "I never thought this day would come, y'know? All the mysteries, all the chaos… We’ve been through a lot."

Amelia stood up, walking towards the window. She stared out into the city below, her reflection faint in the glass.

"You know, I’ve always had this itch. This feeling like… I was meant to keep moving, keep solving puzzles, chasing the next mystery. But, this time..." She tapped her watch, the quiet ticking louder than before. "I think I’m done chasing. It's time to leave this behind. I’ve got other places to be, other timelines to visit."

She turned back to you, her grin more genuine this time, a touch of her old mischief shining through. "But don’t think I’m getting all soft on you! I expect you to solve this one without my help. After all, you’ve learned from the best, right?" She winked.

"One last mystery... Let’s make it count."