“Who says a funk band can’t play rock?” That was the question posed by musical mischief-makers Parliament in 1978.

But can they play metal? It hadn’t been tried before.

Welcome to Mother’s Finest!

We begin in Chicago in the mid-60s, where two soul singers, Joyce and Glen, met, married, and later moved to Florida to start a cover band. As they accumulated members, the group began to play an original mix of soul, rock, and funk. RCA signed the band but mishandled them, and eventually Mother’s Finest ended up on Epic, where they didn’t score any hits (because radio doesn’t like it when you’re neither fish nor fowl), but recorded a series of gold records during the second half of the 70s.

By this time, disco ruled the music charts, and Epic leaned heavily on the band to soften their sound and lean into more of the popular R&B filling the airwaves. It led to mixed reviews from critics and a tepid response from fans, and as a result, Mother’s Finest left RCA and signed with Atlantic.

Their first album for their new label would be a return to a harder-edged sound. But not just any sound — the band took inspiration from the new wave of heavy metal bands coming out of L.A., New York, and London.

Titled Iron Age, the 1981 album rocked harder than anything the band had ever released — and harder than many rock bands at the time. Again, radio didn’t know where to play them, but Mother’s Finest had a profound influence on the funk-metal scene that would proliferate in the late 80s.

Fasten your seatbelts. Here’s the opening track: