Tank tops and skintight American flag apparel mixed with ties, button-down shirts and khakis at the Stars and Stripes Music Festival held on Saturday night at Flatbread Company. The festival is organized each year by Lizzy Plapinger and Derek Davies of Neon Gold Records to benefit the YMCA. Donors and club kids shared the dance floor, while Vineyard teenagers shared the stage with international acts currently at the top of the music charts.

The event raised over $100,000 for the YMCA.

High school freshman Kasey Stevenson started the night off. Usually she can be found on stage at Alex’s Place at the YMCA, but she performed with the presence of a seasoned musician at the larger venue. Kasey’s classmates, Liam Weiland and Tessa Whitaker, took the stage next, performing Falling Slowly by Glen Hansard and Marketa Irglova.

Charli XCX brings some stardust to Flatbread. — Ivy Ashe

The first national act of the night was Great Caesar, an up-and-coming indie rock band. Great Caesar was standing in for the X Ambassadors, who had to cancel at the last moment, but they made it clear they were not just a rushed replacement band.

The Brooklyn rockers started off big with Generations, a smooth garage rock anthem, complete with sliding distorted guitar riffs. The song built to a massive chorus, with four of the five band members contributing vocals over a progressive drumbeat.

Although many of the songs were serious, Great Caesar approached the stage with a sense of humor and kept the performance lighthearted and energetic. Dirty guitar licks mashed with smooth vocals from John Michael Parker and Camellia Hartman, giving the band a retro tone.

By the time Charli XCX stepped up with her three piece band, Flatbread was filled to capacity. The pop icon was dressed in black, from her jacket to her nail polish. She started the set with London Queen, a fierce, head-banger with a punk vibe.

Kasey Stevenson opened the show. — Ivy Ashe

As the set progressed, Charli XCX brought in more pop, putting a bit of magic on Aaron Carter’s Candy. The climax came on the third to last song, when she sang Fancy, currently the number one track on the Billboard Hot 100. She sang through all of her own lines and overdubbed most of Iggy Azalea’s verses. The set ended with Boom Clap.

Although Charli XCX tops the charts right now, the biggest star of the night was Ms. Plapinger and her band, MSMR. This was Ms. Plapinger’s first time performing on the Island, and at her own festival. When she stepped on stage in a skintight, American Flag one-piece suit, the crowd erupted in a massive cheer.

Throughout the set it looked like Ms. Plapinger was having more fun than the audience. Her smile never faded and somehow she seemed to make eye contact with everyone in the crowd at once.

MSMR opened their set with Bones, slowly escalating into a forceful chorus. The set continued to build momentum as they moved into No Trace and Salty Sweet.

In addition to playing songs off their 2013 LP, Secondhand Rapture, MSMR played two covers. About halfway through the set, they played a slightly more upbeat, pop-infused rendition of the Arctic Monkeys’ Do I Wanna Know. Ms. Plapinger’s soulful voice lent itself perfectly to Alex Turner’s mysterious lyrics. MSMR’s version started off very similar to the original, but at the end they let loose their playful side.

Tessa Whitaker and Liam Weiland performed Falling Slowly. — Ivy Ashe

Near the end of the set, the group blended into a cover of LCD Soundsystem’s Dance Yrself Clean. Again, MSMR’s version started very similar to the original, but slowly they made it their own. By the end, Ms. Plapinger was leaning back on her knees, unleashing frantic screams that had everybody dancing and singing along.

Given the recent storm, it was only appropriate that MSMR ended their set with Hurricane. Ms. Plapinger roamed the stage looking like she wanted the performance to go on forever.

When the Knocks took the stage just before midnight, the concert ended and the party began. Although the show had been going on for hours, the energy was still alive as the DJ duo played funk-infused dance music. They played a handful of fan favorites, but also dropped a few new songs on the crowd, who eagerly danced along. At the end of the set, the audience stormed the stage, dancing with the DJs in a final celebration of a wild night of music.