Dissatisfied with the first Trek feature, Nimoy was reluctant to return for ' by the promise of a dramatic death scene. Nimoy enjoyed the production of the film so much that despite his character's on-screen death he wanted to return for a sequel. The film's success allowed Nimoy to successfully negotiate to direct the next installment in addition to briefly appearing as a reanimated Spock. The resulting film, ' was successful enough that Nimoy was asked to direct once more for '. The following film of the series, the William Shatner-directed ' was initially unacceptable to Nimoy because it called for Spock to betray Kirk and side with his newly introduced half-brother Sybok. Nimoy felt his character had already come to terms with his human-side thus Sybok would have no influence on him, and forced the script to be changed before signing on. Nimoy subsequently organized ', choosing the director, writers and producers. To hand over to ' at the time of "The Undiscovered Country", Nimoy agreed to appear as Spock in the episode "Unification". Nimoy subsequently turned down the directing role on "Star Trek Generations" as he wanted to rework the script, and refused reprising the role of Spock for what was essentially a cameo appearance; and his character's lines were subsequently given to Scotty.