Filmed February 11th to the 25th 1975. This episode was meant to be season one's finale, but additional scenes filmed for The Last Enemy (1976) immediately after this episode made that one the last episode to be completed in post-production. Its title caused ITC to make it the season finale.
Orso Maria Guerrini was dubbed by Robert Rietty (as he did for Gianni Garko on Dragon's Domain (1975) and Giancarlo Prete on The Troubled Spirit (1976)); he also would later voice the spheres on Season Two's The AB Chrysalis (1976).
The gymnasium where Koenig trains with Kendo, is a redress of the Commander's Office.
The shot of the Alphans exiting the eagle on the planet's surface is stock footage from Another Time, Another Place (1975).
The music accompanying the episode's various narrations is "Suite Appassionata" by Paul Bonneau and Serge Lancen. The track used during Luke and Anna's silent communication with the dead is "Picture of Autumn" by Jack Arel and Pierre Dutour.