The character model for King Duplis was previously used as King Thales in A Tale of Two Cities (1983).
The planet Krytis features reused background elements previously seen as the Vine Jungle in It's Not My Fault (1983), the Valley of Power in Valley of Power (1983) and the canyon in Teela's Trial (1983).
The large Krytis bird features an altered design of the Mother Roe seen in Valley of Power (1983), as the Carrock in Betrayal of Stratos (1984) and another variation was seen in The Games (1985).
Script was approved October 4, 1984 and final script revision took place February 27, 1985.