Full Story revisited: Steely Dan’s holy grail

US rock band Steely Dan’s song The Second Arrangement has developed a cult following since it was accidentally wiped in the studio in 1979. Now the family of recording engineer Roger Nichols have found a never-before-heard version – and the community is ‘freaking out’. Guardian Australia audio producer Joe Koning navigates the long journey the Nichols family went through, from finding the recording to sharing it with the world