Megadeth frontman Dave Mustaine attended an event called Heavy Metal in Chicago Comic & Entertainment Expo, and revealed a touching story about the song he wrote for Metallica’s late bassist Cliff Burton.

Mustaine talked about the songwriting processes of his songs and said:

“Music, for me, is timeless. It just doesn’t age. When you write lyrics, depending on what your lyrics are about, I’ve always tried to write lyrics that were timely and timeless so that they mean the same thing today as they would when I first wrote it.

For example, ‘Peace Sells… But Who’s Buying?’That’s a lyric that is as relevant today as it was when I wrote it back in 1983. And believe it or not, that’s one of the tracks that didn’t make it on to ‘Warheads…’ because it’s been on everything else. So it was one of those tracks that were kind of easy to skip, but…”

Mustaine explained how he wrote “In My Darkest Hour” as follows:

“I wish there was an average. For me, there’s no telling. I’ve only written one song in one sitting, and that was a song called ‘In My Darkest Hour’, and that was because someone that I loved very dearly” — referring to Metallica bassist Cliff Burton — “had perished in a bus accident.

And I kind of found out [about] it in a really kind of lame way, because the people that were closest to this friend of mine didn’t tell me. I found out through a pretty far removed party. I was really shaken up over it. And that came like that. Usually, the songs… the music and the lyrics are totally disconnected, and it’s kind of trying to fit ’em all together.”