The rule book introduces the universe and the rules of RACKHAM's new game: AT-43. It is divided into two large sections.

The first part presents the history of Ava and the four armies at war forty three years after the Trauma. It introduces, for each side, factions that will be developed in future dedicated publications.

The second part details all the game rules. There is notably a section dedicated to each game phase. Besides, all the important rules are gathered into thematic chapters shooting, close combat, etc. This second part also offers six exclusive missions usable with any AT-43 army.

The annexes offer a glossary of game terms, as well as gaming aids to facilitate the management of the rules in game. They also contain exclusive information from the dedicated publications for the White Stars of the U.N.A. and for the Therian Project.