Chapter 4 focuses on the ideas and activities of republican underground networks in England and Europe. It addresses the ways in which various groups of republicans conceptualised their cause and their visions for a restoration of the Commonwealth government in England. The Northern Rising in 1663, which saw Neville arrested and led to his banishment from the country, was among the more prominent attempts of the underground community in England to restore republican rule. Sidney meanwhile was driving an agenda for change from the Continent, gathering allies and money to invade England with the help of foreign troops. Ludlow, however, hesitated to join any conspiracies, both out of distrust for the republicans’ European allies and out of fear of jeopardising his position in Switzerland. The conspirators’ activities culminated in the aborted Sidney Plot of 1665, which on the one hand exposed the fractures in the exile community and, on the other, changed the exiles’ longer-term prospects by dashing their hopes for an imminent return to republican rule at home.