 Howard Gordon was inspired to write the episode after seeing two news reports about Project Dante, a robotic explorer created by NASA that had been sent into a volcano. Chris Carter said of the episode, "I think that's the first time in our second season that we were telling what's one of our serial stories rather than our mythological stories. In other words, it was an X-File rather than one of the cosmology shows that explore the characters". However, Gordon felt that the episode allowed him to explore the possible results of Mulder's search for the truth, echoing this in the mindset of Daniel Trepkos and the interactions between the two characters. Gordon noted that "the natural endpoint of this quest for the truth is madness", comparing Mulder's treatment of Trepkos with the events of the novel Heart of Darkness.
