The Boys With the Car-Crash Hearts

Director Alan Ferguson - who worked on Fall Out Boy's last few videos, including the self-mocking clip for Infinity's first single, "This Ain't a Scene, It's an Arms Race" - sees the bespectacled Stump as a skilled character actor to Wentz's leading man. "He's my Philip Seymour Hoffman," he says. Adds Kenneth "Babyface" Edmonds, the unlikely guest producer whom the band recruited to work on two Infinity tracks: "Patrick is one of the baddest dudes I've seen in a long time. . . . He has a great voice -- very soulful." But Stump is self-deprecating to the point where you find yourself reassuring him of his charm. "I hear all sorts of things slung at us," he says, "one of my favorites being the boy-band accusation. I'm like, 'Boy band? I'm fat! If we were a boy band, I'd look good, I'd dance and I'd be charming -- so what the fuck are you talking about?' I write songs, that's all I do."

Until recently, Stump -- who rarely speaks onstage during Fall Out Boy's infamously sloppy live shows and hardly moves from his microphone stand as Wentz and Trohman bounce around him -- was lost in Wentz's shadow. But lately, he's been coming into his own, even producing songs for the Decaydance alt-hip-hop act Gym Class Heroes -- he sings the Supertramp-derived hook on that act's "Cupid's Chokehold," which sits alongside "Arms Race" in iTunes' Top Ten.

On the hotel-room desk in front of him is a silver laptop armed with Apple's GarageBand software, which he uses to record Fall Out Boy demos, hip-hop beats and random experiments. He plays a bunch for me; many of them are startlingly close to the finished songs, and some of the beats sound Hot 97-ready. Two of the funkiest songs on Infinity on High -- "Arms Race" and the album closer, "I've Got All This Ringing in My Ears and None on My Fingers" -- were originally intended to be hip-hop tracks.

The day before, Stump met with Jay-Z to play him beats and discuss production projects -- and last year, Jay invited Stump into the studio to write a hook for a Kingdom Come track. "All of hip-hop showed up -- Jay walks in with Timbaland, then Swizz Beatz walks in. Beyoncé was there, doing that dance you see on TV," says Stump, who was intimidated -- the scene from the "Arms Race" video where all the hip-hop dudes laugh at him is inspired by the incident. In real life, Stump never even got behind the microphone. "I had the worst writer's block," he says. "So I was like, 'I fucked up the Jay-Z thing, so I better write the best fucking Fall Out Boy record ever now.' "

Arguably, he did: On Infinity, Fall Out Boy morph beyond the boundaries of their genre to embrace rhythms and vocal inflections that show Stump's affection for Prince, Zapp and Earth, Wind & Fire. "I was like, 'This dude's got something to prove,' " says Wentz, whose working relationship with Stump has its tense moments -- the otherwise mild-mannered singer punched him in the face once during an argument over lyrics. "I think he was holding back before, so I just let him put the music where his mouth is -- or the music where my mouth is, maybe."

Edmonds -- no stranger to love songs -- was struck by Wentz's achingly personal lyrics, which the bassist said were written about one particular girl. Last year when we first met, Wentz told me the same thing: that many of the new songs he was writing were inspired by a doomed relationship, that the girl in question had driven him so crazy that he'd put his hand through a car window, that he was done with her forever.

It looks just like a scene from a Fall Out Boy video: Pete Wentz and a striking young woman with a septum piercing and an aloof air stare soulfully at each other as they sit side by side. They look alike, their eyes enshrouded in the same amount of makeup. Wentz occasionally takes her hand, but says nothing. They're at a Fall Out Boy photo shoot, and the girl looks camera-ready too: Her hair is a punky shade of red, arranged in spikes. She's wearing knee-high leather boots over strategically torn stockings. Her name is Jeanae. She's just shy of twenty, a hairdresser from Chicago. "This is way more boring than I expected," she says as flashbulbs go off. Wentz keeps sending wounded little looks her way -- and seems unnerved when he sees me talking to her.

Wentz appears distracted as the shoot continues at a warehouse in Williamsburg, Brooklyn, hardly speaking to his bandmates. He does brighten when Stump mentions an obscure Star Wars spinoff: two live-action Ewok TV movies from the mid-Eighties. "You've got to see the second one -- it's awesome," he says. Meanwhile, Hurley pauses from a vegan lunch and logs on to MTV's Web site to see the TRL position of the "Arms Race" video. The site promptly crashes his browser, and he goes back to his food.

Eventually, everyone piles into a van, headed back into Manhattan. Wentz and Jeanae sit in the last row. The conversation turns to Morrissey, Prince and then Young Jeezy's new album: Stump hates the rapper's trademark "ha-ha!" laugh, while Trohman -- the only member of the band who drinks and smokes pot -- is a fan. "We should bring him on tour," he says. "It's my dream to smoke weed with that guy."

Wentz and Jeanae seem to be ignoring this discussion. Wentz has the hood of his sweat shirt up, and they're whispering. Two days later, Wentz will tell me about her, how he can't let her go, how she's crazy, how she's the only girl he really wants. But I'm already starting to get the idea.