Little sex and no nudity in this movie. There is one set of passionate kisses, and he takes his shirt off, but they stop before going farther. However, they wake up together in the the next morning. Sex is NOT implied, in fact, it seems unlikely, but the possibility is left open.

There is the beginning of an attempted rape, but the aggressor is stopped, but not before the victim is seen in her bra.

Brother and sister sleep together in a way that would normally be quite weird, but it is completely platonic, and done because of the danger of their situation.

An adult male attacks and begins to try to rape a teenage girl. She is seen in her bra, but the rapist is stopped before he gets any farther.

There are alien spaceships in the sky. We don't see them doing much, but they obviously wreak much havoc on planet earth. No aliens are seen.