Disappointed by the Motive: Phryne is incredulous that Gerald murdered two innocent people over a box of coins.
Dry Crusader: The temperance union has a significant role in the story, with one of their songs playing over the credits.
Impoverished Patrician: Despite Hilly's best efforts to hide it, Phryne and Aunt Prudence discover the McNasters are struggling. The devoted house staff was let go and Hilly was forced to pay in heirlooms to fund her secret alcoholism.
Never the Obvious Suspect: Averted with the first murder - the guy chasing Frank in the beginning did in fact kill him right after. The other murders are a bit more complicated.
Jane doesn't even look up from her book when Phryne narrowly misses running someone over.
Mr. Butler is similarly unphased when he learns there's been a murder:
Dot: You're just in time, Mr Butler. There's been a murder. Mr. Butler: Will that be one less for dinner, then?
Skewed Priorities: Gerald's fixation on his coin collection trumps everything and everyone. On seeing his mother collapsed and weeping, he ignores her distress to ramble about how he got his precious coin back. And when he noticed his collection had been taken, he comes after them with a knife and murders them when he fights them and the coins spill into the water.
