Group of foreign exchange (Asian? French?) students studying (and partying) in major US city are targeted by Masked Killer
What's the basic plot of a slasher movie? A bunch of horny teenagers or twentysomethings go out to the woods to party and get horribly murdered by some psycho in a mask? A slight variation is having the kids vacationing in some foreign (not USA) country and getting targeted by psychos there.
Let's change things up a little okay? The urban environment is way creepier than the forest and it's filled with hundreds, thousands, millions of examples of the deadliest creatures on the planet. Human beings.