When Nax left his home planet he had no intention of ever returning and he certainly didn't anticipate being dragged back to face charges of High Treason.
Under Natuzzi law, the charge of High Treason carries only one possible punishment: Death.
While the Natuzzi are considered a valued member of the United Planetary Alliance, they are also considered to be notoriously xenophobic. They prefer to keep non-Natuzzis off their planet and out of their affairs.
Under the guise of maintaining diplomatic relations, Nax is abandoned by the UPA Fleet Admiralty. As far as they are concerned, if Nax has broken Natuzzi law, then the Natuzzi can have their pound of flesh and any attempt made to interfere with the Natuzzi legal process would be considered an act of war.
Captain Gavin Mitchell, however, doesn't see it that way. He'll do whatever it takes to protect a member of his crew. Even if it means starting a war that no one will win.