They also communicate by singing, accompanying themselves with one of a score of musical instruments, selected based on the social situation and feelings.

Thissell is a clumsy musician and lacks confidence in the alien society, so he is forced to wear a lowly Moon Moth mask.

Eventually, Thissell solves the mystery by borrowing a slave from each of the suspects and determining their masters' mask preferences before and after Angmark's arrival.

He succeeds in identifying his quarry, but is captured and forced to walk unmasked in public (the ultimate humiliation to the natives), while Angmark masquerades as Thissell by wearing his Moon Moth mask.

Thinking quickly, Thissell cleverly represents his humiliation as an act of unsurpassed bravery, asking if any present would be willing to be so shamed in order to destroy his enemy.