chunk: Kirk takes command of the ship citing his experience, angering Captain Willard Decker, who had been overseeing the refit as its new commanding officer. Testing of Enterprise's new systems goes poorly; two officers, including the science officer, are killed by a malfunctioning transporter, and improperly calibrated engines almost destroy the ship. Kirk's unfamiliarity with the new systems of the Enterprise increases the tension between him and first officer Decker. Commander Spock arrives as a replacement science officer, explaining that while on his home world undergoing a ritual to purge all emotion, he felt a consciousness that he believes emanates from the cloud.