||As the episode opens McCoy is noting in his log that Captain Kirk's behaviour is becoming increasingly erratic, constantly carping at the crew over the most minor of issues. He orders the ship across the Romulan neutral zone, prompting a trio of cruisers to decloak and surround the ship. Subcommander Tal hails them, demanding their surrender. Kirk and Spock agree to beam over to discuss the situation in exchange for two Romulan officers beaming to the Enterprise. The Romulan commander accuses Kirk of deliberately trespassing on Romulan space. Spock reveals the Captain's deteriorating mental state, prompting the Commander to arrest him. She begins a lengthy flirtation with Spock, pointing out that as the new commander of the Enterprise he could order the ship's surrender. She notes that he is only second in command on the Enterprise, whereas in Romulan service he would command a ship of his own, perhaps even a fleet.
Kirk throws himself into the force field on his detention cell, injuring himself. McCoy beams aboard to treat him, but during his examination Kirk attacks Spock; unprepared, Spock responds instinctively with the Vulcan "death grip". Kirk's body is returned to the Enterprise.
There it is revealed that the entire situation is an elaborate Federation ploy - Kirk has been feigning a breakdown in order to give Starfleet plausible deniability for the move into Romulan space. Spock is in on the plan, and merely knocked Kirk out so that he could get back to the Enterprise. The mission is intended to allow the Enterprise to get close to a Romulan ship so as to steal a cloaking device. Kirk is disguised as a Romulan, and beams back aboard their flagship. He is successful in stealing the device, and beams back to the Enterprise with it. Whilst Scotty struggles to install the device Chekov scans the Romulan ship for Spock, a task complicated by the extreme similarity between Romulan and Vulcan physiology.
Spock is located and transported back just as the commander, furious at Kirk's theft of the cloak, is about to execute him. She is caught up in the transporter beam and captured along with him. The Enterprise warps out with the Romulans in hot pursuit. Just as they are about to enter firing range Scotty activates the cloak, and the Starship vanishes. Kirk and his crew return safely to Federation space, and he promises the Romulan commander that she will receive fair treatment and be returned to he people in due course.
||One of the better episodes of season 3, this one combines an interesting story, good action, and interesting character moments. The Romulan commander is especially pleasing in this respect - smart and competent, not a stereotypical evil baddie but just a good soldier who happens to be on the other side. For a while they actually had me believing that Spock was at least tempted by her offer, though of course that was never really going to happen.