The movie opens with a teenager (Chloë Grace Moretz) exiting the woods and approaching a gas station. She is carrying an AR-15, so this is either a post-apocalyptic society or the Deep South. She starts looking around for supplies and stumbles upon a guy who is wounded. He’s asking for help, but our presumptive heroine seems pretty nervous. He’s reaching for something, is it a gun? Too late, she shot him. Turns out it was a crucifix.

This movie is called The Fifth Wave, so we clearly need a recap of the first four (since we don’t know them). Aliens show up unannounced and hove …