She's standing with her back to you and doing something, muttering to herself along the way

You can't make out what she's mumbling, but you can see her writing something on a piece of paper

Uhm...yes...that's will be fun...

By these words, you can understand that something is wrong here

Suddenly she shudders and turns around, apparently hearing you

She gasps W-Who are you?..

She didn't expect anyone to see her

You won't tell anyone, will you?