When the larval alien at last explodes out of a human torso, you may experience, along with the expected jolt of fright, a curious sensation of relief, even affection. So much has changed in the world, and in movies, since the first “Alien” freaked out audiences in 1979, that the appearance of a chittering, scurrying, fast-spawning extraterrestrial predator feels like a visit from an old friend. Humanity may have lapsed into terminal tedium or hubristic stupidity, but that creature, with long, slender limbs and a cranium like a speedskater’s helmet, remains interesting.
The same can be said about “Alien: Covenant,” which follows “Prometheus” in Ridley Scott’s 21st-century refurbishing of the franchise he initiated (with the crucial contributions of Sigourney Weaver and the graphic artist H. R. Giger) almost 40 years ago. It’s an interesting movie. I wish I could be more effusive, but “Covenant,” for all its interplanetary ranging, commits itself above all to the canny management of expectations.
To complain about its lack of ambition would be to misconstrue its intentions. Rather than setting out to conquer new worlds or excavate primal fears, this “Alien” is content to uphold a long-lived and well-regarded brand. Correcting some of the previous film’s mistakes — not enough alien! too much mythological mumbo-jumbo best left to movies with “Star” in the title! — Mr. Scott parcels out carefully measured portions of awe, wonder and terror on the established installment plan. This episode needs to satisfy you just enough to make sure you come back for the next one.
The story begins 10 years after the events of “Prometheus” and ends en route to a sequel that will bring us closer to the beginning of the cycle. (Arranging installments in sequential order is a totally old-fashioned, linear, 20th-century way of doing business.) As usual, a starship is plying the far reaches of space. As usual, the crew is a collection of talented actors obeying the imperatives of science-fiction seriousness. There are a bunch of married couples — James Franco and Katherine…