Yuriko is a 21 year old girl who lives with one of her two sisters... Her oldest sister, before moving away to another country, put a curse on her and now when Yuriko hears a snap of someone else's fingers, her body changes shape to fit whatever clothing she's wearing.
She is prone to being coerced or blackmailed into wearing clothes that might change her.
Yuriko woke up one morning lying naked on top of her bed sheets. She'd fallen asleep without changing into her pajamas last night. She got up and walked over to her wardrobe only to find that it was completely empty.
She looked out of her door and yelled to her sister, "Saya! Can you get some fresh clothes up here?"
"Yes," came Saya's voice from downstairs.
A few minutes later, Yuriko heard the sound of footsteps coming upstairs and then her sister knocked on the door. "I've left a change of clothes outside. I didn't have much choice for you since the washing machine has been busted all week."
"Thanks, Saya!"
Yuriko hurriedly changed into the new outfit that Saya had brought up.