Hired by Sosia's uncle, a senator, to find out who murdered her and by the Roman Emperor Vespasian, to uncover the conspiracy, Falco finds himself on the next boat to Britain.
Sosia's uncle, a senator, hires Falco to determine the identity of the killer and to uncover any conspiracies; Roman Emperor Vespasian also assigns Falco these duties. As a result, Falco sets sail for Britain.