Captain's Glory by William Shatner
With the civil war on Romulus averted, Kirk is finally free to seek out the truth behind the death of his oldest and closest friend. Was Spock killed by the shadowy organisation known as the Totality? A generous offer from Starfleet provides him with the starship he needs in order to reach his goal. Their only proviso: they can call on his help if they need him. What happened to Spock is just one of Kirk's worries: Joseph, his son, is rebelling wildly against the restrictions placed on him at the price of Romulan peace. Is the Totality somehow also linked to Joseph's rage? But before he can find the answers to either troubling question, Kirk receives a call from Admiral Janeway, telling him she needs him to save the Federation. Torn between his mission and his duty, the cause of the Federation must claim him one more time before he can turn his attention either to his friend or to his son.