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.
The stronghold leader reads out a letter from Strain urging his favourite Blighters to clip the Rooks' wings but keep their brains intact for his own amusement, then tells everyone to watch their surroundings.
Lambeth has two strongholds, Battersea Bellows and Echostreet Alley. The borough's other targets are the Templars Martin Church, the Lambeth Bullies and the Fletchers, the bounties Leopold Bacchus, Mildred Graves and Jesse Butler, and the Strain & Boil factory.
The two optional objectives pull in different directions: the leader must die without anyone spotting you, while the captured Rooks need freeing and protecting. Do the quiet part first. Find the leader while he is reading Strain's letter, kill him unseen, then free the prisoners and stay with them through the fighting that follows.
The letter is in keeping with Cletus Strain's reputation for theatrics and games: he wants the Rooks beaten but kept alive so he can enjoy them himself.
Echostreet Alley
Echostreet Alley is a Lambeth gang stronghold under Cletus Strain, named for the screech of trains at Waterloo station echoing through its backstreets. Burn the Blighter heist plans and free the captured Rooks for full sync.
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.
Clare Market
Clare Market is a gang stronghold in The Strand, named for the neighbouring food market and run under Victor Lynch. Burn the heist plans and keep lookouts from calling reinforcements for full sync.