this popped into my head while watching the movie. Just to make sure, this is MY theory on the patronus charm. Please, no one flame me saying 'this isn't true! That's not what she wrote!' I respect JKR for the most part, but, like all fan-fiction, this is my interpretation. That's the only thing that's mine. Everything else belongs to J. K. Rowling.

Sirius frowned as he searched the house. Hermione had disappeared after dinner and he hadn't been able to find her. He briefly wondered if she had slipped outside while no-one was looking. He peered into the darkness and was barely able to make out her shape standing next to a tree.

He was wondering what she was doing when he saw a pure, silvery light surrounded her. The light coalesced into a large animated shape that ran around her, jumping into the air. With a sudden slash of her wand, she banished it and fell to her knees. She had obviously wanted privacy, so he was planning to leave her alone when the soft sound of weeping reached his ears. There was no way he was leaving her like that. Sirius grabbed a thick quilt off the back of the couch and joined her beneath the tree.

Hermione was dimly aware of the presence of another person behind her. She really couldn't bring herself to care until the person wrapped her in their arms. The scent of cigarette smoke and fire whiskey surrounded her. Sirius.

"What's wrong, sweetness?"

"I lost her..."

Who? Ginny?"

She shook her head vigorously, making her curls fly. "My otter. She's gone."

Sirius was momentarily confused until he remembered Harry mentioning that Hermione's patronus was an otter. "It's not unheard of for a patronus to change. Snape changed his, remember?"

"But why?" She cried.

He shrugged. "I'm not sure but I know how we can find out."

With his wand, he sent up a shower of purple sparks. Five minutes later, Remus joined them on the blanket.

"Remus, my patronus changed."

He smiled, remembering how she had showed off her little sea otter with pride. He could also understand her confusion and took her hands into his.

"Of course it changed. Your otter was meant to protect you, and it did, but once you got older and started facing tougher challenges, it changed."

"That still doesn't explain why." She glared.

"Well, to understand why, first you need to understand it." Remus' posture and tone changed subtly. Sirius smothered a smile. He loved it when Remus went into teaching mode.

"Your otter represented your innocent, playful side. A side that you lost as the war got went on."

His fingers traced the angry red scar on her left arm. They were all silent, each one trapped in their personal hells. "It changed about the time this happened, didn't it?"

She nodded, not trusting herself to speak.

"That's because you changed inside. Bellatrix and the Malfoys took that innocence from you and your patronus acted accordingly."

Sirius felt her stiffen in his arms. Something about that sentence had struck a nerve. That was something that needed exploring, especially since he hated mysteries.

"Will I ever get her back?" Hermione whispered. It felt as though she had lost a part of herself. Almost like she had lost part of her soul.

Remus shrugged. "Who knows. Probably not, especially after all you've experienced."

She hung her head in defeat. Remus hated himself for causing her pain. She had already seen things that would make an adult wizard think twice. Why couldn't she have just a little joy in her life?

"You know, my first patronus was an owl."

Hermione looked at him in amazement. "You mean could summon a patronus when you were just five?"

He smirked. "I told you I always had an affinity for charms. However, after I was bit, for the longest time I couldn't summon one. It wasn't until Sirius taught me to accept my wolf that I was finally able to. Trust me, I was upset when I realized it had changed. Now look at me."

He carelessly flicked his wand over his shoulder and a beautiful silvery wolf materialized. It trotted over and licked her on the cheek. She couldn't feel it per se, but the tingle on her cheek was unmistakable.

"I can't imagine my life without her." Remus reached up and brushed his hand over the spirit animal.

Not to be outdone, Sirius held up his wand. "Oh yeah, watch this." He whistled. The silver light blinded Hermione for a moment. When she opened her eyes, She couldn't help but laugh.

Like its owner, the animal was larger than life. The wolfhound, who was roughly the size of a small pony, around the trio a couple of times before tiring itself out and laying down.

She experimented with touching it's head and found the same energy. "

Originally, it was a lion cub that grew in size as I grew. Having the childhood I did, mine changed in reverse. It didn't change until I moved in with James. Then it became a dog. I didn't need such strong protecting anymore. I needed fun." Sirius explained.

She bit her lip. "So it might change again." She questioned.

Remus shrugged. "Maybe."

Hermione nodded. I Hope it doesn't." Reaching down, she squeezed both their hands.

The two men looked at her expectantly. "What?" She asked with all innocence.

"Well what is it?" Sirius demanded.

She drew her wand and called forth a large husky.

They stared in shock .

"MY theory is that it tried to combine you two and this is what it came up with."

Remus frowned with confusion. "O.K. But why?"

Hermione smiled. "Because you both make me feel so safe."

She gave them both a quick kiss and ran inside, laughing, her husky following her.

Sirius laughed. "If she's this excited now, just wait til she learns she can travel on one." He jumped up and ran after her.

Remus stood and began to fold the blanket. To be honest, that was a lesson he couldn't wait to teach her.