I say future. Only because of Oc villains. It takes time for a villain to make a name for themselves, and get Batmans true attention. Not to say sci fi future, I think that doesn't belong in batman. But! A future non the less. If not then 2013 is fine.
Edit: As for plot. We can 1) Follow Arkham Asylum game just a bit, and have it so our villains make a riot to make Batman stuck within. 2) We break out and together wreak havoc on gotham, in a plot to get the Batman. If 2) Then it would go 2 different ways. 1) Direct assualt onto gotham and batman. 2) A devised plan, making the assualts just a ruse. While the top dogs (AKA Joker, Crane, Riddler, Penguin. Any master mind.) Are developing a plan. That plan could be to find out whom batman is. Or, to get those batman may care about, such as Robin, Nightwing, Oracle, Batwomen, Gordan etc.
Arc idea 3) A mash up of the above. Grabbing the best of all.
Now I think I have done enough plotting, and my part in doing so. But will continue with my opinions.