`THRESHOLD' RULES TV'S ALIEN NATION.

Byline: David Kronke Television Critic

THERE'S something in the water, and not just the ominous oceanscapes harboring blinking lights and other revelations in the trio of new prime-time sci-fi thrillers ``Threshold,'' ``Surface'' and ``Invasion.''

Something must be lurking in Hollywood's drinking water for essentially the same idea to have bubbled up in the minds of three separate creative teams at the same time.

All involve strange new life forms arriving on the planet in, on or near oceans and, of the three, ``Threshold'' conveys the dangers it's unleashing with the most urgency.

Carla Gugino, remembered fondly as ``Karen Sisco,'' stars as Molly Caffrey, who is recruited by Deputy National Security Adviser J.T. Baylock (Charles S. Dutton) to implement a confidential government protocol on dealing with extraterrestrial life that she has written, titled ``Threshold.'' A Coast Guard ship on the waters off Washington, D.C., has made contact with a deadlier version of one of those plastic mechanical gizmos that expands and contracts that you can get at the Discovery Channel store.

Its crew went berserk, leaving a trail of blood and mayhem and creepy nightmares and cockroaches marching in lockstep to create a spiraling symbol that contains the invading marauders' intent. The only known survivor - unfazed by rounds and rounds of gunfire - says, eerily and elliptically, of his colleagues, ``They changed.''

Caffrey assembles a team of crack scientists to investigate these disquieting developments: microbiologist Nigel Fenway (``Star Trek: The Next Generation's'' Brent Spiner), language/mathematics specialist Arthur Ramsey (``The Station Agent's'' Peter Dinklage) and physicist Lucas Pegg (Rob Benedict).

Pegg, with a shudder, describes the alien presence as ``a four-dimensional object in three-dimensional space.'' The others use language even more complicated and convoluted. At any rate, it possesses the ability to home in on the inner frequencies of hundreds of ordinary civilians - but how? And why?

Tonight's two-hour premiere of ``Threshold,'' created by David S. Goyer (the ``Blade'' films, co-screenwriter of ``Batman Begins'') and executive-produced by longtime ``Star Trek'' guru Brannon Braga, boasts far more jolts and invigorating exposition than the other two new similar shows manage in their debuts, and does so without skimping much on character development. It makes its intentions far more clear than those series, as well, and also amps up the magnitude of its life-and-death stakes much more quickly than its doppelgangers.

All this makes it more of an attention-grabber but could prove problematic as the series goes forth - will it be able to sustain such a high level of energy and suspense?

To do so, all the producers need do is follow Caffrey's own advice: ``We've got to stare into the face of the unknown,'' she declares resolutely, ``and make damn sure we don't blink.''

David Kronke, [phone]

david.kronke(at)dailynews.com

THRESHOLD - Three stars

What: Carla Gugino stars as a disaster contingency specialist heading a team of scientists investigating an apparent alien invasion of Earth.

Where: CBS (Channel 2).

When: 9 tonight.

In a nutshell: Niftily compelling.