The Jekyll Brothers is a Templar hunt on The Thames against Kent and Raphael Jekyll, smugglers from a seafaring family who route illegal imports through London's ports to the black market and the Blighters. Have a police officer kill one of them for full sync.
Kent is furious that Raphael left him minding the docks while Edith Swinebourne came by. Raphael explains she thanked them for fully equipping the Blighters, then admits she kissed him on the forehead, which upsets Kent even more.
The brothers work for Edith Swinebourne, the Templar overseer of the river. The other Thames Templar hunts are Tom Eccleston and Captain Hargrave II, the bounties are Simon Chase, Emmet Sedgwick and George Scrivens, and the Thames has no Blighter strongholds.
A constable, not you, has to kill one of the two brothers, so set things up so that the police land the killing blow; the other brother can then die however you like. Hearing their argument first lets you see where each one is before you start.
Captain Hargrave II
Captain Hargrave II is a Templar hunt on The Thames against Samuel Hargrave, who killed his father years ago and took over his identity and post patrolling the river for the Templars. Kill him and throw the body in the Thames for full sync.
Tom Eccleston
Tom Eccleston is a Templar hunt on The Thames against London's fastest runner, a Templar messenger who shows government letters to the Order before delivering them. Air assassinate him for full sync.
Argus and Rose Bartlett
Argus and Rose Bartlett is a Templar hunt in The Strand against the owners of the Bed and Bottle, a pub and lodging house linked to several missing-person cases. Perform a cover kill on one of them for full sync.
Beatrice Gribble
Beatrice Gribble is a Westminster Templar hunt against a would-be lady-in-waiting who, after repeated rejections, has told the Templars she plans to kill the Queen's consort. Kill her with a voltaic bomb for full sync.