The noble Ultramarines epitomise the Space Marines, the genetically enhanced warriors who protect the Imperium from its foes. Newly returned from the Eye of Terror, Captain Uriel Ventris must redeem himself in the eyes of his battle-brothers, who fear he may have been tainted by Chaos. When the planet Pavonis is invaded by tau, what better opportunity could Uriel have to join his Chapter in combat and prove that his honour is beyond reproach?