Past Tense?

What tense do I use when I talk about something from a book, TV show.

Say, I just watched an episode of <Insert TV Show here> and I want to write an essay about it, what tense should I use when I refer to the story? For example, "The plot is/was very illogical and the characters are/were horrible." Should I use was/were or is/are? This is very confusing because they both seem to work, but what would be the most common one to use? Thanks!

Thank you for your reply. Which tense do you think is preferred for an english essay? I would say past tense because most of the reading materials are very old (e.g. Macbeth, Hamlet, Lord of the Flies etc.).

    -Xsi

I think it's up to you, Xsi. You can write most of it in the past, I mean when you tell parts of the story, and use the present tense when you want to stress how vivid the scene is/was. Your opinion and your deductions can be in the present tense.