seven o'clock
A courier has been dispatched to the troops of Grenier 's division , which , since yesterday , is encamped at a short distance from Potsdam ; he conveys to the troops the order to march to the outskirts of the city , and to wait there at a carefully designated point for the arrival of a carriage . They are then to surround this carriage , and take it at a full gallop along the road leading to Brandenburg . The king will be in this carriage -- seized in a very simple manner . It has been ascertained that the king drives at seven o'clock every evening to Sans-Souci , and the most minute details of what occurs on this occasion have been reported . A man will , therefore , conceal himself shortly after nightfall near the door by which the king leaves the palace . He will approach the carriage a few minutes before seven , enter it , and noisily close the door as the king is in the habit of doing . The coachman will believe this to be the usual signal , and start .