Pixar sure loves a good dichotomy. It's at the core of almost every one of their films, though Elemental may be their laziest attempt yet. As the title explains, this is a story about the four elements, more particularly, the relationship between one fire element and one water element. And yes, the symbolism is really that shallow.
Ember's parents moved to Elemental City, where the four different elements live together. Her father wanted to open up a shop there, and even though he succeeded, he never really got along with the other elements. Ember is a temperamental young lady, but her outlook on life changes when she meets Wade, a water element.
Props for tweaking the art style just a little. It's subtle and it doesn't make a big difference, but at least Pixar is trying to evolve. The characters are horrible though (Wade in particular is obnoxious), the comedy is bland and the plot is more than a little embarrassing. But it's not their worst, so that's something.