Tenses

What tense should I use when I am talking about events from a novel?

I have to compare two person from the book and also I have to explain what happened between them in the novel. I should convince my professor that I had read the novel. Should I use only simple past or I have to use also present simle?

For example: Charles is (was) the central character in the book. He discoveres( discovered) his first love, who also lived by the see. She is (was) married but he believes (believed) she can't (couldn't) be happy and he becomes (became) obsessed with saving her from her husband.