The book is set five years after the events of Return of the Jedi. The Rebel Alliance has destroyed the Death Star, defeated Darth Vader and Emperor Palpatine, and driven out the remnants of the old Imperial Starfleet to a distant corner of the galaxy. Princess Leia and Han Solo are married and expecting twins. Luke Skywalker has become the first in a long-awaited line of Jedi Knights.
Thousands of light years away, Grand Admiral Thrawn, the last of the Emperor's Grand Admirals, has taken command of the shattered Imperial Fleet, readied it for war, and pointed it at the fragile heart of the new Republic. Thrawn is searching for a Dark Jedi and is succeeding in restoring the Empire. The Republic will be forced to face this new threat with the utmost caution in order to end the Empire's threat to the galaxy.
Gilad Pellaeon, captain of the Imperial Star Destroyer Chimaera, receives word that an information raid on the Obroa-skai system was successful. A retaliatory strike by an Obroa-skai task force is easily defeated by Pellaeon's superior, Grand Admiral Thrawn. On Coruscant, Obi-Wan Kenobi approaches Luke Skywalker in his sleep to say farewell, sending Luke into depression. Leia Organa Solo, three months pregnant with Jedi twins, senses Luke's depression and sends Threepio to speak with him. On Tatooine, Han Solo and Chewbacca offer legal work to Dravis and his smuggler allies in an attempt to solve the New Republic's shortage on cargo ships; Borsk Fey'lya, a New Republic council member and native Bothan, dismisses this gesture as futile.
On Myrkr, smuggler Talon Karrde and his subordinate, Mara Jade, help Thrawn and Pellaeon obtain several creatures called ysalamiri. Afterward, the Chimaera travels to the Emperor's storehouse on Wayland. On the planet, Thrawn and Pellaeon encounter Joruus C'Baoth, the guardian of the storehouse. The ysalamiri that Thrawn brought with him prevents C'Baoth from using the Force within a short radius; with little choice, C'Baoth offers his services in exchange for two prospective students: Luke and Leia. Thrawn sends a group of Noghri to capture Luke and Leia on Bimmisaari, but the attempt fails.
After the failed mission, Thrawn convinces C'baoth to seek Luke while the Empire focuses on capturing Leia. Han decides to suspend negotiations with the Bimmisarri leaders and return to Coruscant; Admiral Ackbar, commander in chief of the New Republic fleet, agrees with Han's decision, while Fey'lya feels that the departure will generate negative attention. Meanwhile, Thrawn launches his first offensive: a series of hit-and-run attacks into New Republic territory.
After another failed kidnapping on Bpfaash, Han and Leia decide it might be best to keep a low profile; they decide to visit Lando Calrissian on Nkllon. Noghri aliens once again attempt to capture Leia. On Dagobah, Luke discovers a metal cylinder and decides to bring it to Lando for investigation. When the protagonists meet on Nkllon to visit Lando, fifty-one of his mole miners are stolen by the Empire.
Hoping to elude the Noghri, Leia and Chewbacca visit Kashyyyk. Han and Lando discuss plans to pay a visit to Talon Karrde as part of Han's earlier mission to obtain cargo ships from smugglers. The Chimaera intercepts a message coming from the Falcon in Leia's voice, but Thrawn knows it is merely a recording; through logical reasoning, he determines that Han and Lando are the only ones aboard, and adjusts his plans accordingly. Thrawn nearly captures Luke in a space ambush; Luke escapes but becomes stranded in his X-Wing with Artoo until the Wild Karrde discovers them.
Luke guesses that the Wild Karrde is either a smuggler, a pirate, or a disguised warship. Still, he takes his chances and goes aboard as he has no other option. Luke wakes up and realizes that he is no longer on the freighter. When he finally wakes up, he notices Mara Jade is in the room with him. Luke and Karrde discuss exactly what Karrde's intentions are for Luke. Karrde is undecided as to what he wants to do with Luke. Han uses Threepio to transmit a message to Coruscant in Leia's voice. Han interprets the message to mean that Fey'lya is gathering forces to possibly push Ackbar out of the New Republic Council. In the meantime, Han and Lando leave the Falcon to meet with a fellow smuggler who is supposed to tell them the location of Talon Karrde's operations.
Karrde alerts Mara to the two visitors on their way in: Han Solo and Lando Calrissian. Since he is still holding Luke as a hostage, he tells Mara to move him into a storage area so that neither Han nor Lando notice anything suspicious when they arrive. Karrde has the meeting with Han and Lando and is intrigued by the New Republic's offer. When Thrawn hails Karrde, he says he needs more ysalamiri and wants to have a talk. He tells Karrde that he is in the market for some new warships. Not long after Luke and Artoo's escape, they notice that Mara is not far behind them. Thrawn insists on sending stormtroopers to aid in a search and rescue mission. Karrde discovers that Han and Lando know about the Imperial visit to Myrkr. They sneak out to the storage sheds to snoop on the prisoner that Karrde is reportedly holding. When they get to the storage room Luke was in, they notice that the door opener was tampered with.
It is the middle of the night on Kashyyyk and Leia is awake. As she gets up she is attacked by a Noghri alien. She successfully defends herself but then the alien stops his attack. Chewbacca and Ralrra burst in immediately and Leia tells them not to kill the alien. Using her lightsaber she disables their ship so they are forced to leave.
As they get closer to the edge of the forest, Luke and Mara fight off predatory creatures. Mara decides to stop for the night and is then swiftly attacked by another predatory creature. Luke tries to scare it off but the tactic does not work. He manages to grab his lightsaber from Mara and he attacks the creature and kills it.
On board the Chimaera, Pallaeon confirms that there are a hundred and twelve transient warships available at the Sluis Van Shipyards. They activate the cloaking shield and set the decoyed freighter toward Sluis Van for their attack. Threepio alerts Lando to the message that Luke has just sent to him. Aves is about to blow the rescue plan by beginning the attack and Lando threatens him with a blaster. As Han and Luke make their way across the archway, Luke signals to Artoo to propel his lightsaber toward him.
The New Republic's X-wing fleet, Rogue Squadron, is at the Sluis Van Shipyards. Wedge Antilles notices a bulk freighter passing through without an escort. The battle has begun and the New Republic is unprepared. The Falcon makes its approach at the start of the battle. Immediately they jump into the fray. Han knows that the Empire has come to steal ships. He watches the battle unfold in disbelief as he notices many Imperial Star Destroyers are around.
Heir was extremely well-received, making it onto the New York Times best seller list. Its influence on the Star Wars Expanded Universe was considerable; the EU had previously been primarily elaborated in RPG games, comic strips and other esoteric media. Heir revitalized and opened large portions of the post-Empire EU (such as the very name of the former capital of the Empire, "Coruscant"), and also introduced some of the most beloved EU characters: Talon Karrde, Grand Admiral Thrawn, Mara Jade and Gilad Pellaeon.
Dead characters mentioned: