I would first have them do a freewriting activity in which they write their thoughts about the terms--moral and ethical. This gives them an opportunity to really make a distinction between the two concepts, and it gives the teacher an opportunity to make sure they students have a clear understanding of the concepts. You might then have them discuss situations in which they or someone they know have had to make moral/ethical choices. This gives them an opportunity to personalize the topic before you even start reading.
Has this been placed in the wrong group perchance? Are you referring to a law case or to the book Hunger Games? If you are referring to the latter you might want to think about how the book shocked you when you read it. These are excellent aspects to talk about if you are thinking about moral and ethical implications. There is certainly much to talk about as this example of a dystopia presents us with a very scary future world where children fight each other to death for food and for the entertainment of the world at large.
I would start by talking about moral and ethical implications of other things that they are familiar with. Then relate it to something that they can understand. After that, you can then explain it in the confines of the new book that you are reading. When you go over things and personalize those concepts, students will have an easier time understanding.