Infiltrate Pluto in the new featured campaign

"Do you like surprises?"
– Alpha Legionary

Infiltrate the Sol System and break down the loyalist defensive systems in the Battle of Pluto single-player campaign, now freely available during the next two weeks! Check out the trailer:
https://www.youtube.com/watch?v=BXj2zF3inXA

Tasked by Warmaster Horus to test and evaluate the defences of the Sol System, the Alpha Legion activates dozens of sleeper cells and agents seeded upon Terra itself and throughout the system. Hidden by this synchronized massive subterfuge, Alpharius leads the Alpha Legion in a harrowing assault upon the Hydra fortress, orbiting Pluto.

Learn all about the campaign in the official announcement:
https://www.horusheresylegions.com/alpha-legion-campaign-battle-of-pluto/