This book begins with the Enterprise orbiting the planet Kyros and preparing for an away mission. Dr. McCoy is directing the first trials of a new technology which gives the away team more abilities. The DOP implant is loaded with a given (alien) personality by directly sending live brain wave signals to the device, I imagine that the ship’s sensors would play a part in the operation. When a member of an away team is given the implant, they can more easily overcome the unknown customs, dialects and behaviours of an alien world, but sometimes a little more of that personality can creep through than they might like.
Spock had been leading the away team on Kyros when he suddenly went missing. It turns out that Spock’s DOP got switched from a logical person to a deeply religious and paranoid person, which causes him to become a preacher and the locals are swept up by his convincing words. With a unexpected radiation storm headed toward the ship, Kirk is forced to quickly come up with a plan to capture Spock.
I find the implant technology to be intriguing , the bumps in Kirks path to find Spock can be gripping and the light splashes of violence are a welcome surprise. Some may not like some of the sexist themes in the background, but I found this story to be oozing with original series flavour.
This is a pretty quick read, I recommend it for young and casual readers. This was first published in 1978, and I think it manages to stay relevant in light of the changes the series has had since then. I found the book to be entertaining, but I’m not sure how this story would do as an episode. The premise is interesting, but I think the payoff could have been better.