What I would do, is ...> the next class I would make a comment of the first part of the movie so that the students can remember what was going on, you can even go into details if they remember. Thats all I can think of. There are other things you can do but its like too much, I mean, like finding pictures of the characters and speak about them, etc.
I hope it can be useful Where do you teach? What country are you in?
Regards