Hermione makes it back...but there's a problem

Hermione hurried as fast as she could on her bare feet, but it was slow going. She had to stop far too often to readjust her robe and stop it from falling and she paused at every corner, listening out for the sound of voices or approaching footsteps.

When she reached the Grand Staircase, Hermione paused; this was the tricky bit.

She would be completely exposed as she climbed the airy staircase and it wouldn't take a genius to work out she was wearing nothing under her ill-fitting robe. Fortunately, the school should be pretty quiet as most students would still be outside, so crossing her fingers and praying, Hermione stepped out onto the stairs.

Hermione climbed as quickly as she could up the stairs leaning against the banister for support; she didn't want to risk dropping her hands in case her robe fell.

By some miracle, she made it upstairs without being spotted. A few corners later, Hermione was stood in front of the portrait of the Fat Lady, the entrance to Gryffindor Tower.

"Dilligrout!" Hermione panted, shivering. Despite the warm spring day, the corridors were very cold for someone wearing only a heavy robe and nothing on their feet.

The portrait didn't move.

"Nice try. The password's changed. And I wouldn't let you in without a Gryffindor student anyway."

"What?" Hermione looked down at her robes and saw for the first time that they were emblazoned with the serpent of Slytherin.

"You don't understand, I'm a Gryffindor!"

"Why are you wearing Slytherin robes then?"

Hermione felt her frustration growing again. Didn't the Fat Lady recognise her? She'd been at Hogwarts for six years!

"Look, this is really embarrassing..." Hermione squirmed, her face turning red. "I sort of...err...lost my clothes...this was all I could find..."

"So you're...naked under that?" when Hermione reluctantly nodded, the Fat Lady burst out laughing.

"It's not funny! Please, just let me in!" She was wasting time; the longer she stayed there, the higher the chance of her being seen!

The Fat Lady finally got her laughter under control and composed herself.

"Alright, I'll let you in, but only if you do what I ask..."

Hermione shivered, both out of fear as well as coldness. She was at the complete mercy of a portrait, with only a borrowed robe to preserve her modesty.

"W-what do I have to do?" Hermione asked fearfully.