A/N: This synopsis is for any readers of "The Four Baristas: Double Shot" who haven't read the first book in the series and would like a quick overview of what happened (and for those who have read it, but forgotten stuff).  Needless to say, it contains spoilers.  Basically, it is a spoiler.

Four baristas—Max, Cora, Cam and Mel—have their camping trip disturbed when an alien capsule crashes near their campsite. The capsule houses an artificially intelligent hologram known as EJ, who informs the baristas that the Earth has been invaded by the Rigellians, an alien race, who—being of very short stature—plan to turn it into a giant sweatshop, manufacturing platform-soles and big hats.

To help humanity fight back, a Rigellian scientist with a guilty conscience has sent EJ's capsule, along with several others, to grant superpowers to Earth's greatest warriors. The plan is discovered and all the capsules but for EJ's are destroyed, so for lack of any better options, he superpowers the baristas.

The tyrannical leader of the Rigellians, Admiral Xarnax Splurmfeen, dispatches an officer (Captain Zlep Flenson) to track down the last capsule, however the baristas befriend Flenson (in part by introducing him to really good coffee) and he agrees to help them save the Earth.

Meanwhile, Splurmfeen is at loggerheads with the Galactic Conglomerate, the galaxy's ruling body. Their regulations specify that certain conditions must be met for the invasion to be officially recognised, such as the surrender of all Earth's leaders, within three days of the invasion commencing. Most have been captured, however the Australian PM is still at large.

Councillor Uva Kwoin, ostensibly present at the invasion as GalCon's representative, is secretly part of an organization dedicated to halting Rigellian expansion, and is behind the PM's escape.

The baristas hatch a plan whereby Max and Cam will take Flenson's shuttle to the orbiting Rigellian battle-station, from which the invasion is being orchestrated, in order to sabotage it, while Mel and Cora will attempt to find the PM and prevent him from being captured.

On their way to the battle-station, Max and Cam's shuttle is captured by Chek Wandoo, a rich, flamboyant, former-playboy from Alpha Centauri, who is on a quest to save the Earth.  In an attempt to become more enlightened, Chek has become a disciple of Pok, the last surviving member of a race of philosopher warriors known as the Flame Monks.  Once they realise the shuttle is no longer in Rigellian hands, Chek and Pok join Max and Cam in their quest to sabotage the battle-station.

Unfortunately, their attempt fails, and while on the station Pok is attacked by Kral Vanar, who is a member of the Ice Warriors, the traditional foes of the Flame Monks.  The attack is foiled by Uva Kwoin, who takes Vanar into her custody, as he is one of the galaxy's most-wanted criminals.

Meanwhile, Mel and Cora are successful in finding the PM, and keeping him safe from the Rigellians until the invasion deadline has passed.  In the midst of these events, Cam proposes to Mel, by radio.

 As GalCon's conditions have not been satisfied, the Rigellian authorities are forced to call off the invasion; however Splurmfeen, unaccustomed to failure, gains his revenge by deactivating the battle-station's engines, setting it on a collision course with the Earth. He then makes his getaway in an escape pod, taking the keys to the station with him.

Three of the baristas race against time to capture Splurmfeen, while Cam stays on the station with EJ, to try to restart the engines. Mel accepts Cam's proposal, again by radio. Splurmfeen is killed and the keys lost, however EJ engages in a digital battle with the station's central computer, takes control of the station, and manages to get the engines back on.

By this time, however, the station's dive is irrecoverable. The Earth appears to be doomed, but at the last moment EJ and Cam activate the station's scrunch-drive (which allows interstellar travel), thereby avoiding the collision.

The Earth is saved, however the station's uncontrolled jump into scrunch-space leaves it lost in an unknown part of the universe.

Earth is welcomed as a new member of GalCon (with the former Australian PM selected as Earth's ambassador), while Max, Cora and Mel mourn the loss of Cam and EJ, and resolve to find them.  Meanwhile, Splurmfeen turns out to not be quite as dead as everyone thinks.  Teaming up with the escaped Ice Warrior Kral Vanar, he sets out to wreak his revenge on the Earth, the baristas, GalCon, and the Rigellian authorities, whom he feels have betrayed him.