More Than One Way to Kill a Cat

"Well, thought Harry, did you want to hear my list? A snail plague, an unsolicited pet, a missing client, a missing spade, noises in the dark, a whole nest of dead cat and kittens, and - did I mention it? - another missing client! Talk about being over it."

Harry is a gardener, who occasionally has to kill things for a living - weeds, insects, snails. This makes him a murderer, according to his five-year old daughter Martha. She wants a snail for a pet, before he "petticides" it. But a cat will also do.
On the same day that Martha's pet arrives, Harry discovers something buried in a client's garden. But then the client disappears. While Harry is confronted with deaths and disappearances, his wife Nancy goes on a wild goose chase searching for the meaning behind the find. Harry learns there is no easy answer to the question: when is killing murder?