Revealed at last, the full story of Jim Kirk's lost friend, the man who helped him become the captain we know.... Stardate 1312.4. — A young Captain Kirk, early in his legendary career, faces the crisis of his life when he must kill his best friend in order to save the Enterprise. Later, alone in his quarters, be cannot help recalling how he first met Gary Mitchell: At Starfleet Academy, Gary is reckless and fun-loving while Kirk is driven, ambitious, but awkward around other people—especially women. Their friendship begins with a fistfight. Then their routine training mission on the U.S.S. Republic is diverted to a planet where centuries of bloody interplanetary conflict are about to end in a ceremony of reconciliation. Assigned to help with security on the planet's surface, Kirk and Gary quickly find themselves in the middle of a life-and-death struggle against terrorists determined to disrupt the ceremony. With the future of two planets at stake, Kirk and Gary must find a way to work together before a mission of life and peace becomes one of death and despair.

Continuing the powerful story of Jim Kirk's lost friend, the man who helped shape a Starfleet captain.... Gary Mitchell is dead, killed by his best friend for the sake of his ship. As Captain Kirk returns home in sadness, he recalls the first time he held Gary's life in his hands: Seven years earlier, the two men have been assigned to the U.S.S. Constitution, Gary as chief navigator and Kirk as second officer, when the starship comes to the defense of an alien world menaced by ruthless invaders. An early attack leaves both the captain and the first officer in comas, and Jim Kirk must take command for the first time. He finds himself with only one chance to defeat the heavily armed enemy—but the cost may be Gary Mitchell's life!

The gripping conclusion to the story of Jim Kirk's lost friend, the man who helped shape a Starfleet captain… Captain Kirk has returned to Earth to attend the funeral of Gary Mitchell – the man he was forced to kill. As he wonders what he can possibly say in eulogy, he thinks back to the first time he had to do without his friend, several months earlier… Kirk has just taken command of the USS Enterprise and brought along Gary as navigator. Kirk has learned to depend on his friend's good sense and advice, but when Kirk confronts the Klingons for the first time in his career, Gary is taken captive and cut off from Kirk. Now the young captain has no choice but to rely on a man he barely knows, a Vulcan named Spock.