BTOOOM! Complete plot
The only way you can know of the ending and how the plot actually unfolds is to read the rest of the chapters you haven't. Since the final volume hasn't been translated and released yet, you either need to buy up to the last translated volume and buy a raw version of the final volume and be able to read Japanese, or ask someone you know who knows Japanese to at least give you a rough idea of what happens. I would not rely on the wikia pages for this manga as they are not updated, which might mean that either contributors to the site only read scanlations or they haven't got the time to update yet.

So far, I can't find sites similar to wikia that actually details what happens per chapter so the only options you have are what I mentioned above. Unless, of course, someone here on the site actually follows the manga, understands Japanese and has read up to the final volume.