This story has spoilers, please don't read if you haven't completed the game.
The air was chilly which led Harley to realise the attire she had donned was not the most practical. She looked down at her exposed arms and gently rubbed the rope marks. That big ugly bats, she thought. Thinking he can leave me there all tied up. He doesn't know I've gotten out of worse situations. I'm gonna kick his butt when I see him and his stupid face!
She clenched her fist at the thought, glaring at the large metallic doors keeping her from her Mister J. He was in the theatre, showing that fat, ugly bat who is boss. He had told her to back off and let him deal with Batman by himself. Anything for you sweetie, she had replied. He's gonna come out with stupid bats corpse and we're gonna run Arkham City together! And we're gonna get married and our children will take over, we'll rule this crummy town!
"Hey, Harley!" shouted one of the many guards who were trying to rid Arkham of that smelly Batman. "You're looking kinda angry, baby. Come over here and let me calm you down!" he roared with laughter. Harleys faced flared with anger. She dashed over to him, lifted her legs high in the air and kicked him straight in the face. He fell to the ground clutching his skull and groaning in agony.
"Listen here, bozo!" she snapped, stamping on his chest. He groaned; she was in heels after all. "When my Mister J comes outta there, he's gonna kill you and your silly friends and we're gonna get new and better guards who aren't lame like you! Now Strange is gone Arkham is OURS I tell ya! Stupid!" she stomped on his face and whether he fell unconscious or died, Harley didn't care.
"Let that be the lesson to the rest of ya!" she yelled glaring at the other guards who had began to back away slowly. She heard one of them mutter, "bitch is crazy..." but chose to ignore it.
"Come on puddin' don't keep your Harley waiting," she muttered, dancing on the spot to warm up. After what seemed like hours but was more realistically several minutes, the doors began to open and a hulking figure began walking towards them. That can't be my Mistah J! He's not big and fat like that!
The outline slowly became clearer and confirmed Harley's worst fears. The dark knight was carrying what seemed to be a dead Joker in his arms. Harley's eyes widened, she slapped her hands to her mouth and let out a gasp. Tears prickled in her eyes as Batman headed towards her with the love of her life hanging limply in his arms.
"I am sorry," he said when he reached her. He placed Joker's body at her feet and straightened up. "I was going to save him, but he-"
"YOU KILLED MY MISTAH J!" she screamed, launching herself over Jokers body and pummelling her fists in Batmans chest. "You bastard! Did you not think of me when you did it! He is all I have! I'm nothing without him!"
She broke down sobbing and slid to the floor. Her heart felt like it was ready to burst. She couldn't breath. Panic, anger, sadness all the emotions she could handle washed over her.
"You're safe," said Batman. "You're safe from his crutches, Harleen. I've seen what he's done to you, now you're free. Go and live a normal life. You're better off-"
"FREE!" she screamed, causing a few crows to leave nest. "You took him from me! For what? You want me to suffer? Well I'm suffering here, you stupid, ugly beast! Leave me with him! LEAVE ME ALONE!"
She scuttled to his side and threw herself on him. He was still warm and still smelled like her Mistah J. A noise behind her told her Batman had used his grapple gun to escape. She was too weak to fight, she could barely see through her tears nor lift her head.
"Jokers dead?" said one of the guards. "Now what do you do? Never liked the creepy bastard, but-"
"LEAVE US!" bellowed Harley. She mustered all her strength and pushed herself up. Reaching for a knife in one of her pockets she threw it. It landed in a guard's forehead who instantly crumpled to the floor. She shrieked angrily and stormed forwards to wrestle a gun off another guard. Bullets filled the air as she shot in any direction, screaming for the sake of her bleeding and broken heart. Panicking, the men surrounding her fled but she carried on shooting until the gun was empty. Dropping the gun with a bang, she fell to her knees and crawled towards her deceased lover. Sobs wracked her body as she cradled his corpse, tears fell from her blue eyes and soaked his purple suit.
"S-so what if you w-were a psychopath," she croaked. "You were MY psychopath!"
She would have got up and searched for Batman, hunted him down and killed him but she was nothing... nothing without her . He had made her what she was and without him, she was worthless. She wanted to die; if her heart was broken, why should it still be beating? She couldn't find anything to end her life with but she figured if she stayed her a long time, holding her Mister J, her body would slowly shut down due to the cold and lack of food.
"Till the end," she whispered, squeezing his ice cold hand. "Me an' you against the world, puddin' pie. I can't live without you, so I'm not going to. Simple as that."
Her sobs slowly trailed off as snow began to fall the ground. Probably something to do with that snowman. Hopefully he had managed to kill Batman and stepped on his stupid face. She shivered, her body temperature dropping to a very dangerous level. The only noise that could be heard was the occasional croak coming from her throat. Fatigued, her eyes slowly drooped and her body felt completely rigid. She couldn't even smile as she imagined herself seeing her pumpkin again, even though she didn't really believe in the afterlife it was the only thing keeping her going.
The last thing she heard was a gentle thud, followed by some footsteps inching towards her before she eventually blacked out and blissfully hoped her life was slowly being sucked from her body.