The Decemberists have always been high on ambition and their fifth album is yet another conceptual coup in which a woman named Margaret is abducted by a villain known as “The Rake,” while a political character (“Valerie Plame”), a child murder, and other deaths visit the picture. All of which suggests the Decemberists have at least one foot in the progressive rock ambitions of the ‘70s. The additional use of Jethro Tull-like dynamics and orchestration suggest this Portland, Oregon ensemble are ready to take the complete plunge and pretend as if the past three decades never happened. Yet, one doesn’t have to pay strict attention to the plotline or lyric sheet to appreciate the melancholy of “Isn’t It A Lovely Night?” One might want to keep a scorecard to keep track of the impressive cast of voices, ranging from Robyn Hitchcock to My Morning Jacket’s Jim James to Lavender Diamond’s Becky Stark. It’s a 17-part musical that breaks down into digestible smaller pieces for the conceptually challenged.