"Worth the wait," host Laura Linney says at the outset of the "Downton Abbey" sequel, and for once, the claim isn't just hype. A near-flawless follow-up to writer Julian Fellowes' Emmy-winning miniseries, this expanded seven-part, 10-hour presentation (including two-hour chapters) seamlessly picks up where the original began, brilliantly juggling a plethora of characters -- both the great home's privileged family, and the servants toiling on their behalf. WWI is creating fissures in the bedrock of their insular world, but it has done nothing to dim the glow of a production that genuinely merits the weighty "Masterpiece" label.

For those who might have missed the original, the first suggestion would be to correct that. But to briefly recap, the story centered on the Earl of Grantham (Hugh Bonneville) and the fate of his massive estate, destined to pass to a new male heir -- Matthew (Dan Stevens), so anointed after other relatives died aboard the Titanic -- and whether the house will stay in the family by wedding him to one of Grantham's three daughters.

Just as the first season was ending, however, the outbreak of war intervened. It's now 1916, and the family and servants are adjusting not just to life during wartime but to a shifting social structure and class distinctions, as well as the tragedy of lives and loves lost.

Fellowes hasn't reinvented the wheel, with elements of "Upstairs, Downstairs," Jane Austen and his own "Gosford Park" running through the dizzying array of stories. Yet he has created such a vivid group of characters and assembled such an impeccable cast -- effortlessly oscillating from comedy to drama -- that the hours fly by, addictively pulling viewers from one into the next.

In this environment, a wounded soldier's fate can throw the family for a loop, as can old scandals and grudges. Perhaps most improbably, Fellowes has created a for-the-ages romance between an earnest housemaid (Joanne Froggatt) and a middle-aged gentleman's valet (Brendan Coyle), whose stoic virtues transformed him into the most unlikely heartthrob of the New Year.

While it's tempting to single out others in the sprawling cast -- and fans surely harbor personal favorites -- it would be remiss to ignore Maggie Smith's wonderfully imperious turn as Grantham's mother, the Dowager Countess.

If anything, the backdrop of war has enriched Fellowes' writing, which also benefits from several new characters, including a nouveau-riche newspaper editor ("Game of Thrones's" Iain Glen), who begins courting Lord Grantham's daughter Mary (Michelle Dockery), even though she's harboring regrets for having refused Matthew's proposal.

Aided immeasurably by John Lunn's melancholy score, this is, quite simply, the most romantic melodrama TV has witnessed in ages. The lone disclaimer would be that PBS has withheld the finale, and with a few strained developments in the sixth chapter, it's difficult to see how Fellowes can resolve the multitude of plots as neatly as the war did in season one.

Having already broken HBO's hammerlock on the longform Emmys, "Downton Abbey" would seem to have few mountains left to climb. Given the admiration the first miniseries won, one suspects this might be the rare PBS production that generates sizable ratings.

This is a production that reminds people of the rarefied air PBS can occupy, creating a stately showcase for elegant and (let's face it) older-skewing material. For years, conservatives have lobbied against public broadcasting, dubbing it liberally biased or simply superfluous. For the next seven weeks, anyway, the rejoinder is simple: Find anything on commercial TV equal to the grandeur of "Downton Abbey."