She was only dimly aware of the heavy metal door clanging closed behind her and shrouding the cell, her cell, in darkness. She'd been manacled to the stone wall by her wrists, her tender flesh being bitten by the cold iron every time she tried to move. As she was being forced into the cell she'd asked to use the bathroom first but the only reply she received was laughter and one of the guards informing her that that is what her knickers are for.
Now as Bellatrix stood shivering in the cold, dank, dark room she felt the first trickle of urine run down her leg and she sobbed quiet tears at the humiliation that followed.
As her tears froze on her cheeks she heard a sound on the other side of the door. A distant sound. She pressed herself back against the cold, stone wall as the sound drew nearer. It was a sound similar to that of a scurrying rat but somehow far more menacing. She opened her eyes as wide as she could and tried to focus in the gloom of her cell. A faint glow of distant light shone through a narrow window. It was only just enough light to discern that the thing on front of her had no face. It scurried around her, sometimes touching her, tutting at the wetness at her feet.
Bellatrix stifled a cry of alarm and tried to sink into the wall behind her more but only succeeded in getting stray tendrils from an ancient cobweb caught up in her curls. The dementor laughed, the sound meanacing and echoing in the stillness of her cell. It moved away from her a little, it's back against the door, watching her every movement, delighting in her fear.
Bella, once she realised she had a little breathing space, tried to move herself into a comfier and warmer position. More noises were made by that creature, tormenting her further. She slid down the wall, her manacled wrists rising above her body and her knees tucked under her chin. A small amount of warmth was creeping back into her body but where her wrists were cold in the cold iron manacles they chafed causing a searing pain.
The dementor watched her with amusement before rasping to her Bellatrix Lestrange, Welcome to Azkaban, your own private hell until the day you die". It was then that the real torment began. The dementor showed her images of her childhood, a small dark haired child always alone and never cuddled by her parents, a dark haired child being crucio'd for failing to keep her bedroom tidy. Then images from her marriage followed, of Rodolphius raping her, of Bella being degraded whenever possible by her husband.
The dementor watched it's handiwork with glee, savouring her fear and humiliation, wondering how long it would take to break this member of the noble house of Black