In just a few months, summer will officially be ushered in by the rowdy crowds of Dover, Delaware’s Firefly Music Festival. The heat will be sweltering but Firefly’s 2015 lineup might be even hotter. Perennial favorites like Kings of Leon, Modest Mouse and Spoon will be joined by talented relative newcomers like the Griswolds, Generationals, Hozier, Benjamin Booker and PHOX. Despite all these great musicians, though,Firefly’s top headliner is still missing from the lineup released today; speculation is circulating but what we do know is that whoever this year’s headliner is will make a fantastic contribution to the Firefly Festival. You can see the full line-up here.