Harley Quinn and Nightwing: Unexpected Relationship

The Warehouse

"We'll be safe here, Harley." Joker said, entering the warehouse placed atop a mountain surrounded by trees.

"And we're alone... Batman will never find the two of us here." Harley replied.

"Do you really believe that?" A dark and low voice asked from above. They looked up and saw his empty white eyes glowing.

"Batman!! You made it to the party, come sit down, let's have a talk." Joker said, smiling.

"Speak of the devil..." Harley muttered.

"Bats... There's one of you and two of us... We can't play with you, that would be unfair, wouldn't it?" Joker said.

"Wrong again, clown boy." Nightwing said in a corner, making his Arnis sticks glow to reveal him.

"Well, Let's get this party started then." Joker said as Batman landed on the ground and begun their fight. Harley charged at Nightwing and took out her hammer, knocking Nightwing out of the Warehouse and out into the blistering cold.

Unknown to them, they weren't alone. There was a fifth person in the distance, and in his hand he held a detonator.

"If you think blowing this place to bits and killing both of us is going to keep you out of Arkham, you have another thing coming." Batman said while they were fighting and balancing on the metal just below the ceiling.

"What are you babbling at about, Batman? I know nothing of a bomb." the Joker replied.

"Oh no." Batman said.

He dropped down from where they were, trying to detonate the bomb.

"I can't crack it!! It wasn't you, you aren't this advanced..." Batman said, failing to defuse the oblivious bomb.

"I'm out of here." Joker said, running for the exit. Batman ran after him.

Too late. The bomb exploded, making the two of them fly to the door.

Nightwing and Harley both stopped their fighting, gasping at the sight of the burning Warehouse.

Nightwing ran to Batman while Harley ran to Joker.

"Batman... he didn't set off the bomb... someone else did. Find out who did, Harley..." Joker said in his dying breath as Harley cried.

"Joker didn't detonate it... I know who it was... It was..." Batman died before he finished. Someone shot his chest using a sniper.

Nightwing looked. In the distance he could see his silhouette. A man with a round face, probably wearing a helmet that glimmered in the moonlight.

"There you are... Who are you?" He murmured.

Harley screamed, rushing to Nightwing with her hammer raised.

"Stop!!!" Nightwing said, smashing the ground, making sparks rush to Harley's feet.

"I have to find who set that bomb. All villains in the Arkham Asylum are suspects. Including you." Nightwing said, pointing at Harley.

"So are you." Harley said back.

"I couldn't kill Batman..."

"Yeah, but Batman swore not to kill... Who knows, maybe you didn't." Harley reasoned.

"I'm going to Arkham... You're one of the suspects." Nightwing said again.

"No, I'm going with you, but not in handcuffs. I'll help find the killer." Harley replied.

"What are you suggesting?" Nightwing asked.

"A temporary truce until we find the killer. then I'll happily surrender myself to Arkham." Harley said.

"Done." Nightwing said.

"Now, the question is... Who killed the Batman?"