After the release of
The Motion Picture, executive producer
Gene Roddenberry wrote his own sequel. In his plot, the crew of the
Enterprise travel back in time to set right a corrupted time line after Klingons use the
Guardian of Forever to prevent the assassination of
John F. Kennedy. This was rejected by Paramount executives, who blamed the poor performance and large budget ($46 million) of the first movie on its plodding pace and the constant rewrites Roddenberry demanded. As a consequence, Roddenberry was removed from the production and, according to Shatner, "kicked upstairs" to the ceremonial position of executive consultant.