talk to petra in the reef to start this questline.
you will have too hunt taken zealots while patroling earth, venus, and mars. i found it quickest to move across the planet until i found taken, rather then waiting in one spot. once you start killing taken be sure to search fr a major any time it says a luitenet is poisoning the air. once you kill enough, the zeqlot will apear, the fight is timed so be quick. a fireteam is strongly recomended.
proceed throuhh the questline doing this twice at each planet.
once you are done helping petra, variks will have a questline for you, first you must patrol rubicon wastes, where the cabal strike on mars starts. wolves will prowl. defea the archon and get the next step. the rest is is a simple series of missions. the final boss can teleport you to him thouhgh. so if you hear a mechanical sreech be prepared to run. turn in the completed quest for the trophy.