At 6 hours and 37 minutes, Friday's Powerhouse – the Power99 FM's hip hop and R&B summit – at Wells Fargo Center was this season's longest rap session. Beyond long, what Powerhouse proved to be was a rare and worthwhile celebration of the Philadelphia rapper as superstar with a bill topped by Meek Mill, Lil Uzi Vert and a surprise PnB Rock pop-up during Mill's set.

Nu-soul hop goddess SZA (raised in Maplewood, N.J.) rounded out the top's slots with a dynamic full band set and huskily jazzy vocal riffs. With songs such as her "Supermodel" becoming an instant classic, one wished there would have been more feminine energy during Powerhouse's headlining slots (G-Eazy, Yo Gotti and Lil Baby were decent, but lacked sparkle).

At this point, however, all eyes are on Mill.

Meek was detained for 171 days — November 2017 to April 2018 — at the State Correctional Facility in Chester, and his jailing (and the hassles he continues to face) became a movement of  "Free Meek Mill" billboards and buses, with the rapper an inadvertent and improbable exemplar for criminal justice reform. The might of "Meek as activist" meme got a workout last week: He received Billboard's Impact Award and, pre-Powerhouse, it was announced that he'll take part in a first-ever criminal justice reform summit in Los Angeles with CNN host Van Jones and Kim Kardashian West.  The last time Philly witnessed Mill on stage was during a Made in America "homecoming" appearance and a guest shot during Drake's recent Wells Fargo gig, where each squashed their year-long beef.

Dressed in a woolly cap and sparkly pants, Mill – right before midnight – launched into a sturdily, hook-less set of crowd favorites, new and old, while asking his audience to shout out the names of anyone in their lives lost to wrongful imprisonment, organizational injustice, and senseless gun violence. He professed love and respect for anyone who rode with him while he was in lockdown, and those who tweeted "Free Meek Mill," repeatedly. "I want to shout out anyone who gave me the support for the year I was away," he said in a deep voice. "Lights up for those who lost someone in 2018 – to war, to cancer, to the streets, to the system." Occasionally, that shout came with a middle finger.

Between all the talking  and ending his set with his now-anthemic "Dreams and Nightmares" and its "I used to pray for times like this, to rhyme like this. So I had to grind like that to shine like this" rallying call, Mill ripped through bits of recent tracks such as "Stay Woke," and "Dangerous." The latter featured local pal and singer-rapper PnB Rock who stayed on stage for a nice chunk of Mill's seemingly short set (35 minutes?), and did his own thumping "Everyday We Lit" with some AutoTune sugar added to his caramel croon.

Another Philly rap hero, Lil Uzi Vert, hit the stage before Mill. Wearing a fur collar, a Phillies cap,  and a self-proclaimed set of the "most expensive jewelry" in the place, Uzi proceeded to prance across and stalk the stage while rapping spare hits such as "Rock Star" and "Get Over It" backed by deep slabs of bass and dramatic piano lines. With a voice eerily sinister and weirdly theatrical (imagine Billy Porter from American Horror Story: Apocalypse and Pose rapping), Lil Uzi Vert was the evening's most flamboyant performance – a showmanship from which his predecessors would have benefited.