I've been working on my synopsis lately and here's what I've come up with:

Ion trusts no one, especially when it comes to the Gods of Olympus. Just thinking about the way they toss around their powers like toys, brings a pit to his stomach every time. But as an ancient band of Titans, who were deposed by the Olympians, break free of their prisons deep beneath the Earth’s crust, and threaten the existence of the human race, Ion discovers that his role in the war is much bigger than he expected. For his blood runs like that of the very thing he hates the most…a god.
Now, desperate to stop the Titans and overcome his disliking of the gods—with whom he fights for: Ion and his friends must journey into the modern day world of the humans, battle their way from city to city in search of three mighty jewels that could cease the Titan’s reign, while learning to manage each other’s egos and the pressure of saving the world from enslavement.

I was wondering if this is what I could use when sending query letters to agents. Thanks, Nick