At this point in the Sci Fi Channel series "Battlestar Galactica" -- three seasons down, one to go -- it would be nearly impossible to jump into the story and fully appreciate what has gone before or some of the plot twists that undoubtedly lie ahead.

The new, flashback-heavy "Battlestar Galactica" war film "Razor" (9 p.m. Saturday) is strictly a for-the-fans affair. Even then, it will best be appreciated by those who remember what happened in the second season when the Battlestar Pegasus made a surprise return, commanded by brook-no-dissent Adm. Helena Cain (Michelle Forbes, in a wonderfully steely performance).

"Razor" offers more backstory on Cain and her crew, depicting events fans have only heard about and showing what happened from the point of view of a heretofore unknown young officer, Kendra Shaw (Stephanie Jacobsen), who continued to serve on Pegasus after Cain's death when Lee Adama (Jamie Bamber) took charge.

It's Lee's first mission as commander that sets the stage for flashbacks to both Cain's command and a Cylon War battle when his father, William Adama (Edward James Olmos), was a young man.

The flashbacks to young Adama (Nico Cortez, overdoing his Olmos vocal impersonation) are also presented in a series of two-minute shorts that have been airing on Sci Fi Channel Friday nights during "Flash Gordon" and can be seen at SciFi.com until "Razor" premieres. Some of these shorts are included in "Razor," but fans will want to check out all seven for better context and to see a cool scene of young Adama in hand-to-hand combat with a Cylon centurion while falling through a planet's atmosphere.

In "Razor," Kendra encounters a missing link in Cylon evolution -- the same one Adama comes upon in flashbacks -- and hears a dire warning about the future of the Galactica fleet that's sure to have repercussions when the show's final fourth season begins airing in April.

Written by Michael Taylor and directed by Felix Alcala, "Battlestar Galactica: Razor" jumps around a lot and is likely to confuse all but the most die-hard fans with impeccable memories. My suggestion: Watch it with other fans so everyone can help pull together the pieces of this section of the epic story.

Even after doing that, I still felt the need to re-watch "Razor" and I discovered new bits of character information that sailed past me the first time. "Galactica," as always, is densely layered and demands rapt attention to be fully appreciated.

Like the most recent third season, "Razor" again offers some shades of the Iraq War -- both the terrorists and the Bush administration -- with Cain curbing civil liberties and squelching dissent. The film's title itself refers to the ability of a soldier to become an unflinching human weapon.

"Sometimes we have to do things that we never thought we were capable of, if only to show the enemy our will," Cain says. "When you can be this for as long as you have to be, then you're a razor. This war is forcing us all to become razors. If we don't, we don't survive and then we don't have the luxury of becoming simply human again."

Other reasons to tune in: Lee Adama faces difficult decisions of his own; Cain's relationship with another character explains some of her cold retribution and a trio of old-school, "By your command"-declaring Cylons make a cameo.

And, as with the best "Galactica" episodes, "Razor" will leave fans eager for more.

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