This is a Map inspired by the Castle Moat Cailin from Game of Thrones.
It's a bit of a plot twist however. Ramsay Bolton has send Reek aka Theon Greyjoy as an envoy to Moat Cailin to negotiate the surrender of the remaining Iron Born holding the castle. Only in this scenario the Iron Born have decided to take Theon captive and demand now a high ransom for Theons freedom. Outraged, Ramsay gathers his troops to storm the castle and take it by force.
In this siege you can either play as the attacking Bolton army or you can try and defend the castle taking the side of the Iron Islanders.