Moses (Val Kilmer) is raised alongside Rameses (Ralph Fiennes) in the Pharoah's palace but discovers that he was actually adopted and is Hebrew, not Egyptian. He flees into the desert after accidentally killing a slave overseer and has a religious awakening, returning to Egypt in order to free all the slaves, now under his former brother's control.
This is the Old Testament story of the Exodus, complete with 10 plagues and the parting of the Red Sea. If you grew up in a Christian or Jewish household, you are familiar with this. If you did not, the movie might be a little more inaccessible. It isn't really interested in telling you why Moses does anything; more just assumes you already know, so it presents a version with a high-gloss finish. It is a musical and the soundtrack is very good, which covers a lot of the narrative shortcuts. Also, the animation is top-notch. There are some really beautiful scenes in this, and it looks mostly hand-drawn with only a few CGI elements.
I remember when this came out, but I don't think I watched it until it was on video. I listened to the Whitney Huston/Mariah Carey end credits song probably a thousand times though. If you don't do anything else, give the soundtrack a shot. Unfortunately, the movie isn't available on streaming except for rental. Might be worth it to you; but I'd suggest trying to find a copy at the library first.