Head To Metropolis.

"So where do you suggest we go Super-Dick?" Harley asks you.

You look around and see a there are quite a few temporal rifts scattered around, they seem to be blinking in and out of existence, holding form for a few minutes at a time then closing before another one appears.

"Well it seems we're spoiled for choice" you reply "But as some of these obviously lead back to Gotham we should forget about those for now. That leaves the ones that are Metropolis bound and" you pause, staring intently into a rift about 100 yards to your right "I think THAT'S the one we should go through"

"Huh?" Harley says, a puzzled expression on her face "What makes you say that?"

"Look closely Harley, tell me what you see?"
Harley stares intently into the same rift that you are.

"I see" she begins "I see that it isn't closing like the others"

"Which means?"

"Which means that someone or something wants us to go through it."

"Clever girl" you smile at her "What else?"

"Well" Harley answers "It seems that there's one HELL of a light show going on"

"That there does"you nod in arrangement.

Inside the rift you can see bright lights explode and dance their way back and forth like something from a 70's rock show, the sight accompanied by the sound of massive explosions that seem to shake the very portal itself each time they erupt. As you approach the opening a boulder sized chunk of metal comes screaming through just missing you both as you throw yourself's to the floor.

"Holy shit" Harley yells "Did you see the size of that thing!"

You turn and look at the perfectly spherical piece of metal that nearly decapitated you and watch with wonder as it dissolves into dust.

"Well this might not be the smartest idea I've ever had" you say "But what the hell, hate to be tardy to the party"