Mindshadow (Star Trek #27)

The tranquil planet of Aritani has suddenly come under attack by a vicious and unknown enemy. The U.S.S. Enterprise rallies to the scene, only to plunge into a deadly nightmare: Spock is found mysteriously injured, his mental powers crippled and weak, and Kirk uncovers an evil Romulan plot– with a cunning double agent in the middle. Kirk strives to expose the agent, but only Spock’s knowledge can stop the Romulans.