Star Wars The Black Fleet Crisis

The Black Fleet Crisis is a Star Wars book series written by Michael P. Kube-McDowell. The series consists of three books: Before the Storm, Shield of Lies, and Tyrant's Test.
In Before the Storm, Han Solo and Chewbacca are tasked with discovering the source of a new threat to the New Republic, a fleet of highly advanced warships known as the Black Fleet. Meanwhile, Leia Organa Solo faces political turmoil as the Senate debates the role of the New Republic's military.
In Shield of Lies, Han and Chewbacca work to uncover the true intentions of the mysterious alien race behind the Black Fleet while Leia struggles to maintain the unity of the New Republic against growing opposition.
In Tyrant's Test, the New Republic must confront the Black Fleet in a final battle for the fate of the galaxy, while Han, Chewbacca, and Lando Calrissian face their own personal challenges.