Twenty years after the Battle of Endor, Leia Organa, now in her 40's and holding the position of Senator, is frustrated by the stagnation of the New Republic's Galactic Senate, which is troubled by inaction thanks to the rivalry of opposing factions. The Populists, a faction of Senators including Leia, desire that individual planets be autonomous, while the Centrist Senators support a centralized galactic government. Hearing allegations that the diminishing influence of the tyrannical Hutts has given rise to a dangerous cartel headed by the Nikto crime lord Rinnrivin Di, Leia races to the planet Bastatha to investigate. To her chagrin, she is accompanied by young Senator Ransolm Casterfo, a priggish Centrist with an idealized view of the fallen Galactic Empire. As she expected, Leia is abducted by Rinnrivin for a clandestine meeting, where she learns that many Niktos revere her as the "Huttslayer" for her killing of Jabba the Hutt decades before. During her escape, Leia and Casterfo find common ground, and soon determine that a shadowy greater power is behind Rinnrivin's expansive operation.
A motion passes in the Senate to potentially create a First Senator position (similar to the Old Republic's Supreme Chancellor) with enhanced powers over the rest. Leia, the most likely Populist candidate, narrowly escapes a bombing. Casterfo and Leia's assistant Greer Sonnel discover a sizeable, well funded secret paramilitary organization calling themselves the Amaxines on the obscure planet Daxam IV. The seemingly frivolous Lady Carise Sindian, a Centrist senator from Arkanis, is actually an agent of the First Order, a clandestine organization made up of Imperial loyalists plotting to depose the New Republic and reclaim control of the galaxy. She learns the secret that Darth Vader was Leia's father, and uses it to sour Casterfo's growing trust in Leia. Feeling betrayed, Casterfo makes the secret public, which turns much of the Senate against Leia and effectively ends her candidacy. Leia leads Greer and the X-wing fighter pilot Joph Seastriker on a mission to infiltrate an Amaxine warrior base on the remote oceanic planet Sibensko, which Leia has connected to Rinnrivin as well. They discover a massive military force complete with ships and weapons, and Leia's husband Han Solo arrives just in time to aid in her escape. A firefight results in the destruction of the entire base, but Leia and her team flee with evidence that Rinnrivin and the Amaxines were indeed subordinate to a mysterious larger operation.
Leia presents her evidence gathered on Sibensko to the Senate, and is supported by Casterfo. Furious, Lady Carise and her faction frame him as a supporter of the Amaxines, and he is arrested for treason. Knowing Casterfo faces the death penalty on his home planet of Riosa but powerless to save him, Leia realizes that the Senate is too corrupt to be saved. She calls together some old friends—including Admiral Ackbar and Nien Nunb—as well as Greer, Joph and new "recruits" such as Snap Wexley and Dr. Kalonia to form the Resistance, an underground movement to investigate and fight against the forces amassing to threaten peace in the galaxy.
- This novel effectively acts as a prelude to the events of Star Wars: The Force Awakens, as it gives a look into how the Resistance forms, the machinations of the First Order and how Leia becomes a leader of the Resistance.
- The alien race known as the Nikto revere Leia as "Huttslayer" for her killing of Jabba the Hutt in Return of the Jedi.
- The secret of Darth Vader being Leia's father is revealed to the galaxy at large. This acts as the catalyst for Leia to become General of the Resistance.