Speculative fiction is a broad umbrella category of narrative fiction referring to any fiction story that includes elements, settings and characters whose features are created out of imagination and speculation rather than based on attested reality and everyday life. That encompasses the genres of science fiction, fantasy, science fantasy, horror, alternative history, and magic realism.
A poor ambassador of Earth learns that there's a time to be
diplomatic – and a time when good old human cunning is the only
alternative, when he comes up against an alien race whose weapons are
meaner than his.