The two contrived the plan for an "infernal machine", a volley gun with 25 gun-barrels which could be fired simultaneously. Morey took the plan to Theodore Pepin, chief of the Society of the Rights of Man "Section Rome". After a meeting, they decided to build the weapon, splitting the cost of 500 francs between Pepin and Morey, with the penniless Fieschi building it and being paid for it. After much drama, the volley gun was completed and ready to be used. The gun was built in the place it was intended to be used – a four-room apartment on the third floor of No. 50 Boulevard du Temple. This was on the expected route the King and his entourage would take during the annual review of the Paris National Guard.