The popularity of The Decemberists is certainly perplexing if you think about it too much. The band's stats on paper certainly don't lead one to believe that these guys are reigning indie kings. I mean, they're led by a dorky dude caught in a time warp who warbles on about gypsies and chimney sweeps. Who knew this was the secret to a tour full of sold-out shows. You can never be too "different" in this genre in order to be successful; you just have to write good songs. And if The Decemberists know one thing, it's how to write a song.

When a guy from Montana with a Creative Writing degree and an obsession with 19th-century Russian rebels starts an indie rock band, you just know it's going to be interesting. Singer Colin Meloy uses his wonderfully weird pipes to croon theatrically quirky and ambitious tunes that leave you both enraptured and giddily confused. You can sing along to these tales hundreds of times before suddenly realizing you have absolutely no idea what he is talking about.

Meloy's epic lyrics are backed and fortified by a cosmic array of eclectic instrumentation. The resulting grand sound seems a product of a bygone era and a distant land. Meloy's songs tend to champion the unheard plights of such characters as French legionnaires, seafarers, aristocratic Jewess gypsies, and other "castaways" that society scornfully shuns. The band's fantastical leanings and eccentric musicality is rooted in folk but is transformed, Decemberists-style, with swirling acoustic guitars, rapturous organs, accordions and even a theremin. The music often has a jovial beat that offsets the morbidity of the lyrics. You've never heard "pop" like this.

It's Meloy's off-kilter wit and sophisticated songcraft that likens them to such influential bands as The Mountain Goats, Belle and Sebastian and Neutral Milk Hotel. But really, The Decemberists are truly like no other. I don't remember any other band playing the Soviet Anthem before taking the stage (what is this, Rocky IV?), or bringing a massive gong with them on tour, or having nearly as captivating a stage presence. We may not fully understand The Decemberists' world, but we're sure glad to scratch our heads as we rock out to it, buy all their albums, and see them every time they tour. And that might be the most remarkable thing of all.

Opening is Baltimore's indie heartthrob, Cass McCombs, a crooner in the purest sense. A singer/songwriter with a slurring and swooping register, McCombs mixes dark humor, surrealism, and a hint of tenderness into his work to create songs that manage to be quirky while retaining focus and clarity. The words "refreshingly original" and "intriguing" have been used by critics to describe McCombs's music. But who cares about critics? His songs are just really good and, at the very least, worth a listen.

The Decemberists play with Cass McCombs, Wednesday, October 19th at Metro.