Jedi Apprentice 16: The Call to Vengeance

Shortly after pledging his love to Tahl, she is killed in the midst of the crisis on New Apsolon. Qui-Gon will stop at nothing to put an end to the conflict and punish her killers–even if it takes him to the Dark Side. Obi-Wan struggles with his own bond with Qui-Gon, hoping to keep his Master from crossing a line from which he can never return. The secret rebels on New Apsolon are no longer the only danger for the Jedi; the battle is internal as well.

This is the climax of the series set on New Apsolon.