Star Trek: The Next Generation wanted to have Walter Koenig guest star as his Star Trek: The Original Series character, Pavel Chekov. In fact, an episode had been planned that would have been mostly between Chekov and Worf—two unlikely characters put together. But the connection is clear when the idea is fully explained.
Koenig had pitched the idea of having Worf hallucinate his character, but Story Editor Naren Shankar wanted to go in a different direction. In this episode, Chekov would have come aboard the Enterprise after he’d spent years as a prisoner-of-war. He’d finally been released and was able to leave the planet, and he took a position as an ambassador to help the Federation begin diplomatic relations.
What no one aboard the Enterprise would have known was how bitter Pavel Chekov was and what so many years of being incarcerated had done to him. He felt like the Federation had abandoned him after he’d been taken prisoner, and he was allowed to be tortured and left to suffer on his own. (Hopefully, they would have revealed why he hadn’t been rescued as I can’t imagine Captain Kirk and his crew leaving Chekov behind.) The major plot reveal would have been the real reason for Chekov’s presence aboard the Enterprise—he wanted to sabotage the Federation’s diplomatic relations. Though it wasn’t fully explained, as Worf was Chief of Security, obviously, he would have been the one to uncover the plot.
As nice as Chekov was on The Original Series, it would have been difficult to see him so twisted with hate, but it also would have been understandable and an interesting episode. I would have loved to see how Koenig would have portrayed such bitterness and how Worf would have responded to his “lack of honor” when it came to sabotage.