As usual, eNOtes itself has a particularly full summary of the plot of the novel, plus some very helpful discussion of the book as well (see link below). When searching for this kind of information, it's always useful to begin by going to google and doing the following kinds of searches:
eNotes title of work
Salem on Literature title of work
Magill title of work
eNotes provides access to an enormous amount of information about an extraordinary number of literary works. Indeed, I find it far more comprehensive than any of the single data bases to which my university subscribes. eNotes is, in my opinion, a tremendous value for the money, particularly because of this question-and-answer feature, which is peer edited (an important point) and which is unlike anything else I know of in any other site offering information about literature:
As the eNotes web site itself explains,
Our content is all fact-checked, edited, and written by professionals who are experts in their field. It comes from our in-house publishing unit or from Academic Publishers, including content which is not available online anywhere else.
So, always remember to take full advantage of your subscription to eNotes!
In the meantime, here are some additional sites that may be of help to you:
As you can see, the eNotes discussion is far more detailed that any of the discussions just cited.