Into the castle

Ginny was still holding on to the skirt, trying to prevent it escaping, when Hermione shouted another spell. This time the flagstone floor in front of Ginny opened up, forming a trapdoor where it had been solid a moment before. One more slap on her behind caused Ginny to overbalance, and she tumbled head-over-heels into the trapdoor.

For a moment she dropped through the air, then she felt dusty old material enveloping her. Ginny realised a hanging tapestry had broken her fall, but she had barely registered this before there was a harsh, loud ripping noise and she fell through the tapestry, dumped onto a cold floor.

Ginny looked up, past the ruined tapestry. No trapdoor. Hermione must have closed it behind her, and was probably now lecturing the other students on what Ginny had done wrong in their brief and embarrassing duel.

Then she looked down. At some point she had lost her grip on her skirt, and was now reduced to white floral bra, pink panties with a love heart across the back, white socks and black shoes. And no wand, she had left that behind when she fell. And she was somewhere in the castle, she wasn't sure exactly where.

Ginny jumped to her feet as she heard voices approaching.