Steed and Tara follow a chain of couriers passing a sophisticated briefcase that's carrying a large payoff for an unidentified traitor within the government.
A red attaché case is being transported by a chain of enemy agents though the avengers are unsure of its contents and its ultimate recipient - believed to be a traitor in the government who will receive a large pay-out on delivery. Having beaten the couriers and obtained the object in question Steed and Miss King must use their musical skills to - literally - crack the case.—don @ minifie-1