“Alien: Covenant”

** 1/2

(R, 2:03)

Ah, the siren song of John Denver. Who among us can resist it? Certainly not the crew of the Covenant, a vessel powered by a golden sail cruising through space with 2,000 “colonists” in hypersleep and years to go until they reach their destination.

But when a shock wave from a solar flare jostles the crew awake, they soon begin hearing a faint transmission of “Take Me Home, Country Roads” emanating from a curiously Earth-like planet. Such sonic waves would be expected if this was “Guardians of the Galaxy,” but this is the “Alien” universe — no place for sunny ’70s singer-songwriters. When the antsy crew deviates from its carefully planned mission to seek the transmission’s source, we know it’s only a matter of time until cosmic crustaceans begin bursting forth from bodies. Take me home? You betcha.

“Alien: Covenant” is, itself, a homecoming of sorts for a well-traveled franchise. Since Ridley Scott’s 1979 original — still the ultimate deep-space horror — “Alien” has passed through numerous directors (James Cameron, David Fincher, Jean-Pierre Jeunet) and a prequel reboot, Scott’s “Prometheus.” That film, more bloodless and brainy, sought to answer questions of origin with some pretty audacious back story and — there’s just no easy way to say this — eyebrowless colossi who created the universe.

In Scott’s “Alien: Covenant,” taking place 10 years after “Prometheus,” the so-called Engineers are, thankfully, nowhere to be seen. Back instead are everyone’s favorite extraterrestrials, those acid-dripping drama queens so fond of making a big entrance. Like some of the alien offspring, “Covenant” is a hybrid: part gory “Alien”-style scarefest, part chilly “Prometheus” existentialism. It’s a tall order of thrills and theology that the ever gung-ho Scott, working from a script by John Logan and Dante Harper, comes close to pulling off.

But while “Alien: Covenant” has an ace up its sleeve — Michael Fassbender times two — the sheer number of tricks “Alien: Covenant” pulls out, some of them lifted from the five earlier installments, adds to a general sense of deja vu, which is no doubt made worse by the many “Alien” rip-offs that now adorn our galaxy. Yet what was once a slithery straightforward monster movie in space has mutated into an impressively ambitious but overly ornate saga. “Alien: Covenant” has plenty to offer but unfortunately requires ample study of “Prometheus.”

The captain of the Covenant (James Franco, for a heartbeat) doesn’t survive the shock wave, leaving the uncertain Oram (Billy Crudup) to lead the crew, which includes Daniels (Katherine Waterston, our more demure, less imposing Ripley), the imprudent pilot Tennessee (Danny McBride) and Walter (Fassbender), an upgraded model of David, the android the actor played in “Prometheus.”

It’s Oram’s decision to detour for the John Denver-blasting planet, which initially looks smart. Once through the stormy atmosphere, they find a beautifully mountainous landscape complete with foggy lakes and fields of wheat. But there are ominous warnings, like an eerie silence because of the lack of any animals or birds. And who planted the wheat? When one of the crew members says he’s going to “take a leak,” he might as well be announcing his imminent death.

When things go haywire, the crew members freak out and make such poor, emotional decisions that you, as in prior “Alien” films, find yourself rooting for the creatures with bike-helmet skulls. They might not be pretty, but they’re not foolish.

The “Alien” films have always been where our idealistic adventuring and world-conquering hubris are brutally brought down to earth, even in the deep reaches of space. That’s why the insertion of an artificial intelligence has been fitting. The lone human(ish) presence on the planet turns out to be David, who has, a la “Apocalypse Now,” been living a godlike existence, lording over his creations.

Not as intensely mechanical as his newer model, he has clearly developed some unusual glitches. He quotes Byron, with jealousy. Like a robot Brando, he sings “The Man Who Broke the Bank at Monte Carlo” while trimming his hair. He’s a kind of frustrated poet who yearns to create like the man who made him.

The scenes between David and Walter have a strange, erotic energy. David, trying to unshackle his fellow android from servitude, urges him to make music and teaches him how to play a recorder. “You have symphonies in you, brother!” he encourages. For Fassbender, an actor capable of precision and madness in equal measure, the dual parts are a feast.

There are moments for Daniels and the Alien, too, as “Alien: Covenant” winds along. But by the film’s belabored end, the franchise has shed its host. This is no longer an “Alien” movie; it’s an android one.