Vanguard is divided into four chapters, with each chapter being a new day onboard the ship.
Vanguard starts with Nik, Jay, Lucy and Ralph inside the Earthen Capitol's famous bar. There, they receive medals due to their actions in the previous novel Silent Dreams. While talking, they decide to go on a cruise and board the HMS Vanguard for a five day cruise.
Vanguard came about as a roleplay carried out on the Garry's Mod sandbox game. After the surprising success of the roleplay, its creators decided to adapt it into a novel with production starting in mid 2016. Following this, Cloak And Dagger Date was recompiled and became a prequel, forming the Vanguard series. Silent Dreams was announced shortly after and takes place between CaDD and Vanguard.