'Legion' stars Dan Stevens in slow-going Marvel series

Dan Stevens stars in FX's 'Legion'

(CNN)"The superhero show that dares to be boring" is a strange selling point, but that's a pretty fair description of "Legion," a loosely connected offshoot of the "X-Men" comic book franchise that operates on an almost wholly cerebral level, including its treks -- slow, surreal and trippy -- through a highly developed mutant mind.

As such, enjoying this FX series will require not only considerable patience but realistic expectations, as series overseer Noah Hawley -- fresh off a triumphant run with "Fargo" and its prequel -- is content to gradually drill down into his protagonist's psyche, without much apparent concern about excitement or pacing.
Dan Stevens (formerly of "Downton Abbey," soon featured in "Beauty and the Beast") stars as David Haller, a man who grew up in and out of institutions. He's not crazy, though, but rather blessed (or cursed) with extraordinary mutant powers that he's been unable to control, which have risked driving him mad.
Subjected to experimentation by shadowy government officials, there's more than a touch of Brian De Palma's "The Fury" in David's plight, although the series was actually adapted from comics spun out of the "X-Men" universe.
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    Still, the pyrotechnics here are decidedly low-key relative to those features, with David occasionally losing his cool and telekinetically shaking the rafters. And while Marvel has demonstrated its ability to produce brooding, character-driven TV shows for Netflix, "Legion" seems destined to test how much commercial appeal that strategy will hold ratings-wise, even on a cable network known for its edgy, risk-taking fare.
    Kicking off with a 90-minute premiere (and the beneficiary of extensive promotion during the Super Bowl), it doesn't give away too much to say that David is eventually liberated from his captors, bringing him to an odd new venue inhabited by more people like him. It's presided over by Melanie Bird (Jean Smart), who also wants to poke around inside David's head, but with the ostensible purpose of helping him, not harnessing his power for nefarious ends.
    That process includes probing David's memories, resulting in a lot of bizarre but unexplained images. While slickly produced, the major question is not so much where "Legion" is heading but how long it's going to take getting there, at the risk of being a bit of a snooze along the way.
    David "may be the most powerful mutant alive," he's told relatively early on, which certainly holds the promise of more galvanizing moments ahead. At least initially, though, "Legion" is intriguing but well short of extraordinary.
    "Legion" premieres February 8 at 10 p.m. on FX.