Three years after the commercially disappointing "Pretty. Odd.," Panic! at the Disco returns without primary lyricist/guitarist Ryan Ross and bassist Jon Walker. However, the emo-pop sensibilities of 2005 debut "A Fever You Can't Sweat Out" are intact, and the exclamation point in the band's name has been reinstated. Vocalist Brendon Urie takes over the songwriting on new single "The Ballad of Mona Lisa" and revisits the vengeful tone of the act's breakout single, "I Write Sins, Not Tragedies." "Whoa, Mona Lisa, I'd pay to see you frown," Urie croons, "there's nothing wrong with just a taste of what you paid for." Musically, "Mona Lisa" is the catchiest track the band has written in five years, brimming with the vaudevillian spirit of Panic!'s earlier works. While the single covers familiar ground, this throwback will certainly be welcome to fans of the group's pre-"Pretty. Odd." material.