As hard as it is to build a dominant ratings night of TV, it can be just as hard to hold onto it. NBC faced that challenge on Thursday nights and succeeded, until relatively recently, with blockbuster series that spanned two decades. CBS, having built viewership on Mondays with "Everybody Loves Raymond," now strives to retain the night in its "win" column without that popular series. In this case, though, the network has turned part of that challenge into an opportunity with a fresh and spirited comedy that slices and dices the genre in ways that should charm viewers.

You might think that "How I Met Your Mother" is about how central character Ted (Josh Radnor) explains to his completely bored son and daughter in the year 2030 how, a quarter of a century earlier, he found his wife. It is that, yes, but it is a lot more. It also is about all of the adventures and misadventures Ted has during the courtship process and even about dating the women that don't end up becoming his wife.

A voice-over by Bob Saget takes viewers back to when Ted, 27, learned that his best friend, Marshall (Jason Segel), a sincere if not terribly bright law school student, was about to propose to Lily (Alyson Hannigan), a vision of sweetness and patience. Although Ted told himself marriage was not in the cards for another three years, news of the impending engagement triggered a nesting impulse. His other good friend, Barney (Neil Patrick Harris), a charming goofball addicted to wearing suits and a self-proclaimed expert on everything, wastes no time introducing him to any and every attractive female who stops by the neighborhood bar.

Things clicked with Robin (Cobie Smulders), a TV feature reporter who seemed particularly well-suited for Ted, though circumstances kept tugging them apart. The story develops through an imaginative blend of splitscreen, flashbacks and jump cuts that come together smoothly and smartly, a tribute to the vision of creator-writers Carter Bays and Craig Thomas and the skills of veteran sitcom director Pamela Fryman.

"How I Met Your Mother" introduces a level of unpredictability not usually found in comedies. There is good chemistry among cast members. In particular, Hannigan, of "Buffy the Vampire Slayer" fame, shows why she should never be off TV for long. Tune in for the laughs, absolutely, but it will be the basic humanity of the series' heart that brings viewers back for more.