"when a single mom and new employee journalist realize that the newspaper closed a case about a multi-international company poisoned the water, she must begin to investigate the case herself, but realizes the strong forces, that will do everything for the company to continue its establishment on the island."

There is a lot happening here, and I feel like you could condense this and make it flow better. Is the single-mother a really important aspect? Is that the only thing that defines the character? Focus should be made more on what is the key issue of the story. So if it is about a conspiracy (or power play) of the company, then from what I gather, something like this could work just as well:

A new and upstart journalist discovers a frightening story that her employer is unwilling to publish involving poisoning of water sources by a multinational company. Unable to accept such injustice, she puts her life on the line to expose the darkness and stop the company – whom will stop at nothing to silence her.