Waging a bitter war of vengeance against Hive Fleet Kraken across Ultima Segmentum, the Scythes of the Emperor must continue to look to the future if the Chapter is to survive.

In a distant system of the Sotharan League, a lone Apothecary has become stranded before a fresh tyranid invasion - and the stock of Space Marine gene-seed he bears is too great a treasure to abandon to the xenos. Striking from the air, Assault Squad Cassander must push deep into enemy-held territory if they are to mount a recovery mission, facing all the winged spawned horrors of the hive ship Daedalus.