Vendetta! - Walkthrough==
Part 1: Building an operational Base of Operations
To the right, you can see where to put the Base of Operations. Connect it with a road so it won't become strange (if it would be a house it would need it)
Part 2: Infiltration and Your Spy
Check espionage for more info.To infiltrate your spy select an enemy house (that is atleast at Citizen level or higher/ or nomad & envoys) and click the button to infiltrate.
Depending on what house you chosen, after your spy infiltrates, he will allow you to do arson/riot/poison/belly dancer/false prophet. Use one of these to lower the enemy's morale.
Infiltrate more houses and you will have new options.
Finishing off Gavin Langton
Remember to Compliment and pay tribute to him. Garibaldi will pay you money for succesful actions. Continue to lower his morale. Try to be effective and creative(new types of sabotage).
Following these tips, you should easily finish the mission.