Jacob's Island is a Southwark gang stronghold in a disease-ridden district long known for villains and radicals. Keep the lookouts quiet and kill the leader undetected for full sync.
The leader asks for volunteers for Plumb's attack plan but grumbles that she was the wrong choice for the borough, since hiding behind reinforcements hardly shows strength.
Jacob's Island is one of Octavia Plumb's two strongholds, the other being The Mint. Southwark's Templar hunts are Phillip Beckinridge and Myrtle Platt, and its bounties are Anna Abramson and Albie Vassell.
Both optional objectives reward a quiet approach. Silence the lookouts before they can call for help, then reach the leader and kill him without being seen. If you get spotted near him, the lookout and undetected conditions can both fail at once, so scout the yard before committing.
The stronghold leader openly doubts Plumb, saying her reliance on reinforcements is weakness. His complaint fits the lookout objective: the Blighters here lean on calling for help.
The Mint
The Mint is a Southwark gang stronghold for Octavia Plumb's Blighters, on the site of an old mansion once used for minting coin. Burn the heist plans and stop lookouts calling reinforcements for full sync.
Battersea Bellows
Battersea Bellows is a Lambeth gang stronghold that Cletus Strain built on a stretch of industrial land once full of housing. Kill the leader undetected and free the captured Rooks for full sync, then claim it for the Rooks.
Black Swan Yard
Black Swan Yard is a riverside gang stronghold in the City of London, an abandoned site Bloody Nora's Blighters took over after several failed developments. Keep lookouts from raising the alarm and kill the leader undetected for full sync.
Blue Anchor Alley
Blue Anchor Alley is a Westminster gang stronghold under heavyweight champion Lilla Graves, on ground once busy with sailors and fishmongers. Burn the heist plans and kill the leader undetected for full sync.