Two young girls with revenge on the brain, in the Big Apple, there's no telling how big or painful their bite will be!

I like the first part of the logline. Sets up for some nice mayhem. However, I do not know whom/what these girls are seeking revenge upon. If New York is essential to the plot line, then keep it, but I think it can be taken out for now and replaced with something we can vilify, such as:

"After a falling out with their parents, two girls hit the big city with revenge on their mind. There is no telling how hard their bite will be!"

or if your keeping New York.

"Fed up with New York city living, two girls seek revenge against the very city they call home. Who knows how big or painful their bite will be?"

It has potential, it just needs to give me something to cheer for. Once it hits that, than things will quickly fall together.