The second season of “Sleeper Cell,” the riveting Showtime miniseries about Muslim terrorists waging holy war in Los Angeles, gets off to a much slower start than the first. That’s a shame because the eight one-hour episodes of “Sleeper Cell: American Terror,” which will be shown on consecutive nights starting this Sunday, steadily ramp up the intrigue and excitement.

Faris Al-Farik (Oded Fehr), the charismatic Saudi leader of the opening season’s sleeper cell, is now behind bars (with good reason: He tried to kill 50,000 people at Dodger Stadium). The only other cell members to survive the climactic ballpark shootout that ended Season One are Ilija Korjenic (Henri Lubatti), a Bosnian school teacher who finds shelter in the loving arms of a Tower Records employee who believes the attacks of September 11 were a Bush-Cheney plot, and the show’s hero, Darwyn Al-Sayeed, the African-American Muslim FBI undercover agent who penetrated the cell and averted civic catastrophe.

Darwyn also managed to preserve his cover, which means he’s good to go for another series. Unfortunately, as played by Michael Ealy, this perpetually hangdog Muslim American hero is one of the most soporific characters ever to head a series as good as this one. His facial expressions rarely exceed two — glum and glummer — perhaps because, among all his other duties, he has the weight of representing moderate Islam on his shoulders.

To its immense credit, “Sleeper Cell” doesn’t flinch from showing the extreme fanaticism, cruelty, hypocrisy, duplicity, and grotesque behavior of the terrorists, and that’s leaving aside their taste for mass murder. A scene from the first series, when three senior operatives convened in one Las Vegas hotel room, was particularly emblematic: Two helped themselves to infidel hookers on the carpeted floor while the third helped himself to blinis and caviar.

Still, one wonders whether the decision by the show’s creators, Ethan Reiff and Cyrus Voris, to make Darwyn a Muslim was dictated by a desire for dramatic complexity or political expediency. Would Darywn be a more impressive hero if he’d simply studied Islam and passed as a Muslim on the strength of brilliant scholarship? As it is, seeing him pray immediately after a close female colleague is beheaded by his co-religionists, as we do in this season’s opening episode, is more alienating than moving, perhaps because the writers are a little too vague about Darwyn’s own interpretation of the religion. (He’s a Sunni but acts more like a Sufi.)

For that matter, how many viewers are rooting for Gayle (Melissa Sagemiller), his white, single-mom girlfriend, to convert to Islam, as she shows signs of doing, even without marrying him, if she isn’t murdered before she gets the chance? And what would Darwyn expect of her if she did? Would it be out with the tank tops and on with the hijab? Would we — meaning non-Muslims — care? How would it affect our view of Darwyn?

There are practicing Muslims involved in the making of “Sleeper Cell,” including one of the writers, so its vagueness on these points cannot be blamed on lack of knowledge. Indeed, the second installment of the series is so chock-full of hadiths and quotations from the Koran (“There is no compulsion in religion,” etc.), often accompanied by wailing Arabic music, that it can start to feel like a recruitment video. “Where is God’s Paradise?” is a question asked of all who would be mujahedeen, and you’ll soon know the answer by heart: “Under the shadow of the swords.”

If only the FBI had such snappy code phrases. The agency is portrayed as even more tiresomely bureaucratic than in the first season and, in the form of Darwyn’s latest case officer, increasingly sinister as well. With Farik imprisoned (he was shot in the knee cap, rather than the head, in the hope he’d talk), the specter of Abu Ghraib also looms large, but the Saudi isn’t particularly impressed by our water-boarding techniques, let alone the controversies they arouse. “You Americans are so obsessed with yourselves,” he remarks, “that you care more about analyzing your guilt than achieving victory. That is why we will win and you will lose.” Change the pronouns and you’re reading a right-wing blogger in a recriminatory mood.

The first season of “Sleeper Cell” revolved around a planned anthrax attack. This time it’s dirty bombs and a plot that spans continents and allows for multiple story lines in Canada, Yemen, Saudi Arabia, Germany, and Bosnia and Herzegovina. Some of them, particularly that of Ilija, the Bosnian from the first season who is slowly moving toward a renunciation of holy war, are engrossing enough to furnish a series of their own.

Though it fails to capture the typical jihadist’s aesthetic distaste for America, which was the most impressive achievement of John Updike’s recent novel, “Terrorist,” “Sleeper Cell” does an excellent job of rendering the implacable nature of radical Islam. “Your world is never going to be safe again until you make peace with Islam, on our terms,” Farik warns in a typical statement.

At the same time, even as the cell moves inexorably toward assembling a dirty bomb, the brittleness of the jihadists’ faith is cleverly evoked. The second season’s new cell members include Mina (Thekla Reuten), a Dutch convert who was formerly a call girl in Amsterdam, and Salim (Omid Abtahi), a closeted gay British jihadist of Iraqi origin whose terrifying fanaticism increases in tandem with his sexual turmoil.

Like many of the jihadists, Salim finds plenty of erotic opportunities in the land of the Great Satan and avails himself of them thoroughly. This underscores the widely held suspicion that sex, both in terms of male temptation and female oppression, is the Islamists’ Achilles’ heel. Perhaps the most devastating scene comes when Farik, who is eventually sprung from jail, persuades his English-educated daughter, who has shown a talent for drawing, to burn her sketches because Islam forbids the pictorial arts.

At moments like these — and there are more than a few of them — “Sleeper Cell” proves itself to be one of the most compelling programs on television. The new season is more introspective than the first in the sense that much of it is concerned with the battle between differing interpretations of what constitutes “true” Islam. Only the failure to address what that actually is prevents “Sleeper Cell” from being television drama at its very best.