The movie explains its premise clearly enough, albeit in a clumsy exposition-heavy voiceover section near the beginning: Philippa Georgiou (Michelle Yeoh) was once the ruler of the bloodthirsty Terran Empire, an evil mirror of Star Trek’s utopian United Federation of Planets. She crossed over into ‘our’ universe and gradually reformed, sort of, before vanishing. Now Section 31—Starfleet’s version of the CIA, more or less—needs to track her down and enlist her to help them save the galaxy from another threat that has crossed over from the evil universe to ours. Emperor Georgiou originated on Star Trek: Discovery, and she was a consistently fun presence on a very uneven show. The performances are almost uniformly bad, ranging from inert to unbearable to ‘not trying particularly hard.’ Every time one of these characters ends up dead, you feel a sense of relief because there’s one fewer one-note character to have to pay attention to.