At any given time, there exists a massively popular band whose massive popularity remains an unknown to even the most astute pop-music observer, and then all of a sudden that secretly massively popular band is selling out MSG and everyone’s like, Whaaa? Sometimes that’s because the band’s foreign (think Muse a few years back), but often it’s because the band’s massive popularity is built upon a bedrock of fanatical tweens, the kind of people your average astute pop-music observer does not, sadly, come in contact with much. For a while there, the reigning secretly massively popular band was My Chemical Romance, the New Jersey emo-rockers with oodles of theatrical stage clothing, carefully applied eye makeup, and giant, giant choruses. But in the four years since their last album, The Black Parade, Jared Leto’s 30 Seconds to Mars has admiringly busted through the actor-rock stigma, using many of My Chem’s tried and true tricks, to more or less claim the title. Now My Chem’s coming back in November with Danger Days: The True Lives of the Fabulous Killjoys, and the second single, “The Only Hope for Me Is You,†is here. Is it epic enough to quash Leto and his minions? Or will MCR front man Gerard Way have to get revenge by co-starring as a monosyllabic bad boy in a beloved teen drama?