After an entertaining acceptance speech, Chicago took the stage and launched into "Saturday in the Park" at the Rock and Roll Hall of Fame inductions tonight.

The band had an on-again, off-again (and ultimately permanently off) plans to reunite with original singer Peter Cetera – but he did, in fact, stay home.

Chicago did reunite with founding drummer Danny Seraphine, who left in 1990. He was visibly emotional about playing with Chicago for the first time in 25 or so years, and slipped right into the band like he had never left. Robert Lamm and Jason Scheff traded off vocals on the laid-back tune, which sounded pristine.

Tris Imboden returned on drums for another on-point song, "Does Anybody Really Know What Time It Is?" Rob Thomas, who inducted the band with an entertaining speech that played up its rock pedigree, joined for a verse and stayed onstage to harmonize with Robert Lamm.

Seraphine — who was playing a kit that had his name in vintage-looking script underneath the Chicago logo — returned to add even more muscle on a smoking version of "25 or 6 to 4," which highlighted Keith Howland's electric guitar work and Scheff's muscular vocals.

In other words, the band played like it had something to prove. And although fans have known for years the group's deserved to be in the Rock and Roll Hall of Fame, tonight everybody realized exactly why Chicago's induction was so long overdue.

Their current tour features a reunion with longtime friends Earth, Wind & Fire. Now More Than Ever, a new documentary about Chicago’s history, recently premiered at the Sedona Film Festival.

The 2016 Rock and Roll Hall of Fame induction ceremony will be broadcast on HBO on April 30.

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