From their website:
Fantasy Flight Games is proud to announce an exciting new board game set to bombard your tabletop later this winter!
In the Horus Heresy board game, the most legendary battle in the history of the Warhammer 40,000 universe unfolds across the razed plains of Terra and in the frozen orbit above. Deadly fighting ranges from the Emperor’s golden Inner Palace to Horus’s flagship, the Vengeful Spirit.
Taking the side of traitor or loyalist, two players control either fearless Space Marine legions or deviant Chaos Space Marines, mighty Titans, Imperial Armies both loyal and traitorous, and a fearsome array of other units, including the Emperor and Horus themselves.