DOOM: Infernal Sky

DOOM: Infernal Sky is the third in a series of four officially licensed tie-in novels to the original DOOM series of games in the mid-1990s. All four volumes were reissued in 2005 with new cover art.

In this book, the storyline breaks with the in-game plot, as the invasion of Earth is revealed to be only part of a larger conflict involving several extraterrestrial races.

Plot summary
Flynn "Fly" Taggart, Arlene Sanders, Albert Gallatin, and Jill Lovelace are resting comfortably at the Marine base in Hawaii. Fly and Arlene recount the story of their escape from Los Angeles; the Marines decide to promote them and erase Fly's criminal record.

In the interim, Salt Lake City has been destroyed by a nuclear strike. Ken, the "cyber mummy" from the previous book, has also been restored to health, with his implants left in place for use in electronic espionage.

The military has just decoded a signal sent by an alien race, warning of the original invasion. The aliens instruct the human race to seek their help by returning to Phobos and reactivating one of the teleportation points, to arrive at an unknown location.

Under a new commanding officer who comes off as a stubborn "by the book" type, Fly, Albert, and Arlene prepare to head back to Phobos - which will require a return to Los Angeles to steal a shuttle. Complicating matters, Jill's skills are needed to infiltrate the facility and she must escape on her own. Albert then proposes marriage to Arlene.

The team secures the shuttle and departs to Phobos. To reach safety, Jill is forced to kill two human traitors, which leaves a deep impression on her.

The Marines eventually reach the Gate and are transported into a strange gathering of many alien races, all in a state of war against the demons (now nicknamed the "Freds" by Marine HQ). The chief representatives, the Klave, assign two liaisons to the humans, who take the names "Sears" and "Roebuck". Few details are clear, but it seems that Earth is only the latest front in a six-million-year war, and the Freds have developed a special grudge against humans.

The aliens and humans assemble an invasion force to attack the Freds' home planet. When an accident leaves Albert unable to accompany them, Arlene marries him - knowing that when she meets him again, he will be in his sixties due to relativistic time dilation.

During its journey, the ship is assaulted by a large spaceborne creature. The crew fights it off, but is forced to land on a nearby planet and use another Gate to escape. The Gate malfunctions, killing the CO and trapping Fly, Arlene, Sears, and Roebuck aboard a Fred vessel. With no clothes or weapons after the teleportation, they fight barehanded, killing the Freds and capturing the ship.

However, this ship is not as fast. It is on a direct course for the Fred homeworld, but the Marines will not arrive for another two hundred years.

Source

 * Infernal Sky (Doom, 3) (No. 3) at Amazon.com