The series follows the employees of I.M.P. (Immediate Murder Professionals), an imp-run assassination company in Hell, on their many different jobs.[9][10][11] The members of I.M.P. include Blitzo (pronounced "Blitz"), the boss of the venture, along with weapons specialist Moxxie, powerhouse Millie, and Blitzo's adopted daughter/receptionist hellhound Loona. With the help of an ancient book obtained from Stolas, a Goetial demon of Hell, they access the human world to complete their tasks on order from souls in Hell.