Answer:
If this is the book I'm thinking of then this question is in my favor. This is The Magician's Nephew that is apart of the Narnia series, right? (Granted, I haven't read the whole book)
The protagonist of The Magician's Nephew by C. S. Lewis is a young boy named Digory. He behaves like any other 'normal' boy. He's got a taste for danger and adventure, and doesn't mind disregarding the rules for the sake of curiosity or invalidation. With his friend Peggy by his side, they are transported into the magical world of Charn. There, they find the queen, awake her, and cause the conflict that disrupts the story. Digory is saddened by this, but determined to make it right.
The antagonist of this story is debatable, but most likely Uncle Andrew. He is greedy, self-centered, and ignorant of the possibilities of magic (and the affect it has on things). Uncle Andrew is only obsessed with power and being the strongest, and he is willing to use manipulation to get what he wants (though he's very bad at this). What he is searching for and unable to find is the power he seeks and the escape from the conflict he inevitably started.