In 1945 Bill Monroe wrote Blue Moon of Kentucky as a slow, sorrowful waltz sung in his high lonesome style. Nine years later, in a sweltering Sun Studio session in July 1954, bassist Bill Black started beating on his upright bass and mocking the song in an exaggerated falsetto to blow off steam. Elvis Presley and guitarist Scotty Moore jumped in, the waltz became a driving 4/4 blues, and producer Sam Phillips declared it a pop song. This episode explores how a foundational bluegrass standard became a rockabilly anthem entirely by accident.

The hosts cover Monroe's 1944 Opry debut of the song, the September 1946 Columbia session at the Wrigley Building in Chicago with Lester Flatt and Earl Scruggs, and the record's early 1947 success. They then follow the Sun release of July 19, 1954, the Memphis radio battle between Dewey Phillips at WHBQ a ...