The Board is Set is the sixty-sixth short story published in The Horus Heresy series that was not originally part of an anthology novel. The Board is Set was first published on day 23 of the Black Library's 2017 Advent Calendar.
Malcador the Sigillite is troubled. The war fleets of the traitor Horus approach, and war on the Throneworld is inevitable. But with the Emperor on the Golden Throne, keeping the darkness beneath the Imperial Palace at bay, how can even the assembled might of three Space Marine Legions stand against the fury to come? Communing with the Emperor, Malcador plays out a wargame, musing on the key pieces and the unorthodox strategies that may be required to secure victory – and at what role he might play in the battles to come.
- The Board is Set (Short Story) by Gav Thorpe