For this one you need to complete the quest "Don't Shoot the Messenger", which becomes available during The Beginning of the End story quest. Head to the bottom of Tycho's Ribs to acquire this quest.
Once you have the quest, head to Triton Flats and find an NPC named Hanna, who is being attacked by Scavs. After defeating the attacking Scavs, Hanna will tell you to deliver a message to a girl in black (Britannia, Tungsteena Zarpedons daughter) in the Up-Over bar on Concordia. Give her the ECHO, and after she listens to it the quest will be complete and the achievement should unlock.