In real life, Joanna of Castile, aka "Juana la Loca," had a rough time. Her parents were the infamous and intimidating Queen Isabella and King Ferdinand: Columbus, Inquisition, Reconquista, consolidation of power, expulsion of the Jews (did you know they weren't allowed to take money, weapons, or horses with them?), and so on. Joanna wasn't even supposed to rule, but a bunch of people died inconveniently, putting the crown on her head. She wasn't a very competent monarch, and then her husband (a cheating jerk) died, and she supposedly went mad, ending her days in a nunnery. Poor Joanna. But in Charise Castro Smith's new play The Hunchback of Seville, "Infanta Juana" is a spoiled, pyrotechnically raving hellion.

Played by the physically small but volcanic Libby Barnard, Juana threatens to hijack the entire show with a temper tantrum so epic, even the playwright—who happened to be sitting to my left on opening night—kept wincing in what seemed like a mixture of pleasure, terror, and astonishment. Books were thrown, cats were bludgeoned to death, and scenery was literally chewed as Juana howled at gale-force volume for far longer than anyone expected. That spectacle is not called for in the script, but it's fully consistent with Castro Smith's nerdily researched but gleefully inaccurate play about a critical world-historical moment in 1504.

Queen Isabella (Maria Knox) is dying before our eyes—sores mushroom on her face between scenes—and doesn't trust her nutcase daughter to rule. So she's come to ask her adopted, brainiac, hunchback sister Maxima Terriblé Segunda (Samie Detzer) to be the kingdom's puppet master. This is a tough ask. Maxima is a proud, dorky recluse who prefers maps, mathematics, cats, philosophy, and her lover-turned-fugitive Talib Furozh (Ali el-Gasseir) to the rest of the world. And, as she puts it to her maid Espanta (Rose Cano): "Hello? Spain is fucked... 99 percent of the people who live here are right-wing Christian fundamentalists who most certainly would not accept a female atheist as their leader, and the other 1 percent are stuck-up douchebag nobility who would spit on me for being a hunchback. The New World is a freaking horrific bloodbath. Why exactly would I want to take the helm of that?"

"Well," her old maid says, "someone's got to." And so the games begin as Maxima's bedroom turns into Grand Central for zany realpolitik, some pleasurably cheap groaners ("What on the flat surface of God's great earth?"), and more meta-theatrical winking than anybody besides an MFA student should be expected to stomach. (The epilogue zings from a riff on A Midsummer Night's Dream—"If we Spaniards have offended"—to something Tony Kushner said at a talk in Minneapolis.) But it's big, careening fun with outsize everything, from costumes to performances. Detzer as Maxima, wearing a fake warty nose and a giant hump beneath her dress, seems right at home in this louder-than-life production directed by Jen Wineman. And it ends, as you know it must, with a bang.