10 Most Shocking Betrayals In Star Trek

If there is one rule about Vulcans that cannot be broken, it is this: Vulcans cannot lie. Therefore, the revelation that Valeris had been playing the crew of the Enterprise for fools the entire time came as somewhat of a surprise.

Valeris was written into the film as the third incarnation of Saavik, played first by Kirsty Alley and then by Robin Curtis. Kim Cattrall did not want to be the third actress to take on the same role and so it was re-written to become Valeris, Spock's protegee. Early in the film she establishes herself as an able ship-man, quoting regulations and acting every bit the Vulcan that the audience expects her to be.

Then, in the dark of the night, she enters sickbay to dispose of those who could uncover her plot. Little did she know it would be Spock himself that she would face.

The crew are stunned. Vulcans don't lie, so how could it be that Valeris could be a part of the plot to scupper the peace treaty between the Federation and the Klingon Empire? When Spock calls her on her lies, she replies simply that she wasn't lying. She chose to tell her own truth. There follows an extremely uncomfortable scene akin to assualt, where Spock forces a mind-meld on her. After this, Valeris is very clearly broken.

Clearly, the betrayal by a fellow Vulcan was a stab that Spock was not expecting. His punishment may truly have damaged her forever.