Aliens have arrived; OK, now what?

Whether because the anxieties of our age (terrorism, impending pandemic, crazy weather) are finding metaphorical expression as popular entertainment, or because “Lost” was such a hit that TV producers can think of nothing better than to get in line behind it, we are knee deep in science fiction, horror and mystery series this fall.

“Threshold,” which begins tonight on CBS, and “Surface,” which surfaces Monday on NBC, are two of the season’s three “invasion” shows -- the third being “Invasion,” which gets underway next Wednesday on ABC.

“Threshold,” like “Invasion,” has a Body Snatchers aspect: Whatever’s out there will triumph by turning us into them. In “Surface,” originally called “Fathom,” the visitors come by water -- though it is hinted that they may have come originally by air -- and it isn’t clear what they want, if they want anything at all, apart from fish. “Threshold” is a comic book, and passable as such; “Surface” is steeped in Spielberg, and is better Spielberg than Spielberg has managed in quite some time.

Like “Surface,” “Threshold” begins at sea, as a spiky folding metallic doohickey that looks sort of like a giant executive desk toy appears to the unlucky crew of a Navy freighter. It makes a horrible noise that causes nosebleeds and genetic mutation before disappearing possibly into a fifth or even sixth dimension. The series’ signature special effect, however, is the fractal-geometric pattern into which schools of fish, hordes of cockroaches, blips of radar and even drops of blood are strangely aligned, a kind of cosmic Busby Berkeley routine. It is fun for a minute or two, but by the end of Night One it becomes no more exotic or dreadful than a postmark. For all the atmospheric weirdness and bursts of crazy violence that fill the show, it isn’t until the end of the first hour that one gets a genuine sense of excitement, and this is accomplished simply by star Carla Gugino having a weird dream and waking up in a sweat. This mood is not sustained.

Gugino -- last seen on TV as “Karen Sisco” and welcome back under any circumstances -- plays a “contingency analyst,” an expert on the really terrible things that can happen to a planet, whose report on What to Do When Aliens Arrive suddenly makes her “the most important person on the planet.” So says secret agent Brian Van Holt, arriving by helicopter to pluck her from the park where she’s gone to walk her dog. Such impractical overkill is characteristic of the show’s level of unreality.

Press-ganged into assisting Gugino are biologist Brent Spiner -- who, as the actor formerly known as Data, brings genre cred to the series -- a former “ ‘60s radical” in a moth-eaten sweater, who goes on about his “rights”; Rob Benedict (“Felicity”), as the nervous young engineer who is “also one of the all-time high ‘Jeopardy’ winners”; and Peter Dinklage (“The Station Agent”), a linguist-mathematician with a “gambling, booze and stripper problem.” Over them all is government guy Charles S. Dutton: “Come on,” he demands of Gugino, “dazzle us with some of your celebrated conjecture.” Each is currently a series of quirks in search of a character -- the normal three-dimensions will do

“Surface” does not suffer that deficiency. Where “Threshold” is all super-brains and super-cops and super-aliens, “Surface” is life-sized: It’s about ordinary people involved in extraordinary events. Even spunky heroine Lake Bell (“Boston Legal”), who glimpses a heretofore unknown aquatic life form on a dive to explore a “hot-vent ecosystem,” is just an ordinary, hard-working marine biologist. She’s a real heroine, because she’s built from the inside out: It’s not just that the script declares her superiority -- we can feel her energy. “Pay attention,” she’s told as she goes off to view the ocean floor. “I was born paying attention,” she replies happily. It might not be obvious because of the context, but Bell’s is one of the season’s great performances, utterly convincing in its excitement and fear and scientific arousal.

Created, written and directed by brothers Josh and Jonas Pate, who have done a couple of minor features as well as the USA Network series “Good vs. Evil,” it is a Spielberg pastiche through and through -- “Jaws,” “Close Encounters” and “E.T.” rolled into one -- but it is an excellent one, and an improvement in some ways on that tired master: less sentimental, more authentically down to earth, not so darn big.

The show takes care of a lot of business in a short time, following multiple story lines -- besides Bell, there is Louisiana regular guy Jay Ferguson (“Judging Amy”) looking for the thing that snagged his brother, and suburban kid Carter Jenkins hatching a sea monster egg in the family fish tank -- without ever feeling rushed or cramped. The Pates know when to go fast, but more important, they know how to go slow, and there is an especially good use of silence appropriate to the unsettling setting. Notwithstanding boats and subs and swimming, the water is the place on Earth that people really don’t belong. We’re as helpless and as alien there as we are in outer space.

The creatures so far are shadowy, and will hopefully remain so for a while. The fact is that the payoff is rarely as good as the mystery. The aliens will be friendly or they won’t, they’ll look like bugs or beasts, they’ll eat us or enslave us or sell us insurance. There are only so many options. And once the monster’s out of the box, it’s just another monster in a long line of movie monsters. “Surface” works because it gives you more than monsters: It remembers to bring the people.

*

‘Surface’

Where: NBC

When: 8 to 9 p.m. Monday

Ratings: TV-PG (may be unsuitable for young children)

‘Threshold’

Where: CBS

When: 9 to 11 tonight (premiere);

9 to 10 p.m. Fridays regularly

Ratings: TV-PG L,V (may be unsuitable for young children, with advisory for language and violence)