Caius ist ein Dummkopf

English title: Detectives in Togas. Originally published in Germany in 1953, this is the first of a children's mystery series set in ancient Rome. Yes, Rufus wrote CAIUS IS A DUMBBELL on his tablet at school, but no, he did not break into the schoolroom, did not tie up his teacher, and certainly did not paint his slur about Caius on the Temple of Minerva (even if it is in Rufus's own handwriting). Rufus is doomed unless his six classmates can find out who is really responsible. Every hour seems to bring a new, confusing clue . . . until the boys finally stumble upon someone who is not what he appears to be.