Historical murder mystery for children set in Rome at the time of Claudius. Adrastos is a slave boy who works in the kitchen. He has a tame monkey. The young Nero, who will one day be an infamous emperor, visits the kitchen hoping to see the monkey. He and Adrastos make friends. Both have a complicated relationship with the adult world whose brutality they have experienced in different ways. Nero's dysfunctional family have tendency to kill one another while Adrastos has barely got a family. Together they roam the streets at night, listen to conversations they shouldn't have heard, while trying to piece together what lies behind the disappearance of a monkey and a dead body.