Myrtle Platt is a Southwark Templar hunt inside a Templar warehouse on the edge of the borough, where explosives and weapons are stored for the Blighters. Kill her using hanging barrels for full sync.
Outside, Blighters welcome reinforcements for Octavia Plumb and fret about the constables, while the constables argue about whether the warehouse is worth searching. Only one of these conversations plays on each attempt. You then get inside and find Platt.
Platt supplies the Blighters of Octavia Plumb's Southwark. The borough's other Templar hunt is Phillip Beckinridge, its bounties are Anna Abramson and Albie Vassell, and its strongholds are The Mint and Jacob's Island.
The warehouse has barrels hanging overhead, and one of them has to be what kills Platt. Wait until she walks or stands under a load and bring it down on her. Staying hidden while you wait keeps her from moving off.
One of the Blighters is worried because he has a price on his head, and another wants to warn Platt about the police. The constables are split between those who think the place is full of soap and glassware and those who suspect something shady.
Phillip Beckinridge
Phillip Beckinridge is a Southwark Templar hunt against a brewery owner known for working his staff to the bone and selling beer that is making the borough ill. Kill him using a carriage 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.
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.