Acacia Little had been by the Doctor's side for years now, ever since Rose Tyler had left. The two had shared adventures across time and space, forming a bond that only grew stronger with each passing moment. They had been through so much together, facing monsters and dangers, unraveling mysteries, and finding solace in each other's company. Eventually, in a quiet moment between the stars, the Doctor had asked her to marry him. She had said yes, and with that, they became even closer, the bond of their relationship solidified by both time and love.

Acacia was different from Rose. While Rose had been impulsive, full of energy, and had brought out a playful side in the Doctor, Acacia was steady and calm. She had a depth of knowledge about the universe and a patience that balanced the Doctor's occasional wildness. She knew how to handle the Doctor's complexities, his darker moods, and his quiet moments of vulnerability.

But everything changed when Rose returned.

The Doctor, still holding the memory of Rose close to his heart, was not prepared for the storm that was about to hit. He had long reconciled with Rose's departure, but when she reappeared—this time, not alone, but with Jackie and Mickey—everything shifted. Rose had been gone, but now she was back, and it was as if time hadn't passed for her at all.

Acacia was on the TARDIS when Rose arrived, and when she saw her, the unspoken tension immediately filled the air. Rose's eyes scanned the room, her expression flickering with confusion as she tried to process the sight before her. The Doctor was standing there, of course, but next to him—holding his hand—was a woman she had never met. The Doctor's face was unreadable, but Acacia could see the deep pain in his eyes as he looked at Rose, knowing exactly what she was feeling.

Rose, however, was not about to hold back. She was confused and hurt, and her voice was sharp as she confronted the Doctor.

"You're... engaged?" Rose asked, her eyes narrowing as she looked between the Doctor and Acacia. Her voice, though steady, carried an edge. It was more a statement than a question, and the weight of it hung in the air like a storm cloud waiting to burst.

The Doctor shifted uncomfortably, his hand tightening around Acacia's. He knew what was coming, but there was little he could say to make it better. Rose was part of his past, a past that now felt like it had splintered into two separate realities. He had loved her, but he had also found something else—someone else—in Acacia. Someone who understood him in ways Rose never had. And now, it was all coming to light, with Rose's return revealing everything that had changed.

Acacia, though quiet, was aware of the hurt behind Rose's words. She had known that this day might come—the day when Rose would reappear—but it didn't make it any easier. She stood tall, her eyes calm and steady as she addressed the woman who had once meant so much to the Doctor.

"I'm Acacia," she said softly, her voice warm but firm. "And yes, I'm engaged to the Doctor." She could see the confusion and pain in Rose's eyes, but she had no intention of backing down. "The Doctor and I have been together for a long time. I've seen him at his best and his worst, and I've chosen to stand by him. We're in this together."

Rose's jaw clenched, her feelings a tangled mess of confusion, anger, and sadness. She didn't know this woman, and it was hard for her to accept that the Doctor, the same Doctor she had traveled with and loved, had moved on. The thought felt like a betrayal, even though she knew she had no right to feel that way.

"You... you replaced me?" Rose's voice cracked, not from anger, but from pain. "I leave, and this is what happens?"

Acacia's heart ached as she saw the raw emotion in Rose's face. She didn't want to hurt her, but she couldn't deny the truth.

"No, Rose," she said gently, her eyes not leaving the other woman's. "The Doctor didn't replace you. He just found something else. Something different. It wasn't about replacing anyone."

The Doctor stepped forward, his hand reaching out to touch Acacia's arm, but his gaze remained fixed on Rose. "It was never about replacing you, Rose. I'll always carry you with me. But we had to move forward. We both did."

Rose's eyes burned with a mixture of sadness and fury, but her voice was quieter now. "I see," she said, her tone thick with emotion. "So, what now? You're just going to go on, like I was never part of it?"

Acacia glanced at the Doctor, her grip on his hand tightening, as if silently saying that they could get through this together. The Doctor nodded slightly, his eyes full of regret, but firm in his decision.

"We're still the Doctor and the TARDIS, Rose," he said, his voice soft but resolute. "But now, Acacia is part of that too."

The room fell into a tense silence, as if the universe itself was holding its breath. Rose stood there, unable to speak, her emotions a storm raging within her. Acacia stood beside the Doctor, strong and steady, understanding the weight of the moment.

The Doctor had moved on, and while Rose may never fully accept that, the truth was clear: life had continued, and for the Doctor, for Acacia, and for the universe they both traveled through, it was all part of the ever-changing adventure that was time.