A Legiones Astartes wandering warrior, clad in grey, kneels before the Regent of Terra and solemnly accepts his new duties. He is Nathaniel Garro, once the commander of the Eisenstein, and now the prime agent of Malcador the Sigillite. Whether on the ruins of Isstvan or in the halls of the Imperial Palace itself, the Space Marine is always ready to engage Horus's treacherous allies in battle. But Garro is on his own path, one in which he will one day question his place in the Imperium... and what if the legionnaire falters like the others?