The writers discussed potential ideas. Ronald D. Moore had previously brought back "Original Series" character Montgomery Scott for the ' episode "", and since Takei was appearing in "Voyager", they decided that having a member of the main cast from ' return would be repetitive. Some consideration was given by Moore to sending the "DS9" crew to the gangster-themed planet visited by Kirk in the episode "". René Echevarria suggested a time-travel episode, which was seen as an expensive proposition. Echevarria, however, pressed for the idea. Moore suggested inserting the "DS9" crew into "The Trouble with Tribbles", saying it could resolve the question of why a constant stream of tribbles kept hitting Kirk in the head.