Story related and can't be missed.
This achievement is unlocked when you have completed all 15 missions.
*** Spoiler - click to reveal ***Mission 1 - Hold On, Kiddo: Find and save Jackson.
Mission 2 - Tools of the Trade: Buy some crafting components.
Mission 3 - Breakable Things: Search Racine Boat Restoration, and kill Robert Racine.
Mission 4 - Collateral: Defend Clara.
Mission 5 - One Foot in the Grave: Track down Tobias Frewer and speak to him.
Mission 6 - A Blank Spot There-ish: Power up the bunker.
Mission 7 - Jury-Rigged: Disable the security terminals.
Mission 8 - Grandma's Bulldog: Track the source of an IP address.
Mission 9 - Not a Job for Tyrone: Tail Tyrone "Bedbug" Hayes and save Gary "Rabbit" Diggs.
Mission 10 - Uninvited: Ambush Delford "Iraq" Wade's men.
Mission 11 - Breadcrumbs: Retrieve information from the auction briefcase.
Mission 12 - Stare into the Abyss: Eliminate Crispin.
Mission 13 - A Risky Bid: Attend the auction, and scan Iraq's ID tags.
Mission 14 - Role Model: Find Jackson.
Mission 15 - Planting a Bug: Guide Bedbug into Iraq's server room and Way Off the Grid: Search for Raymond Kenney.