The Spheres of Heaven

The story revolves around Chan Dalton, who is tasked by pacifist aliens to uncover the mystery behind their disappearing starships while Earth remains under quarantine. The aliens' strict policy against harming intelligent life complicates matters when Dalton encounters hostile invaders. Faced with a dire choice, he must decide whether to engage in battle, risking the loss of their star-faring future, or allow the enemy to threaten Earth’s existence.