A phone call brings terrorism shockingly close to Supt. Harriet Martens and her husband, John Piddock. One of their police-officer sons, Graham, has been killed by a London booby trap, and his twin, Malcolm, is hospitalized in a coma. Any other officer would be prostrate, but the Hard Detective, traumatized and grief-stricken, is back on the job at the Assistant Commissioner’s urging the following day, conducting a discreet one-woman investigation into the theft of CA 534, a souped-up herbicide that’s vanished from the office of Dr. Giles Lennox, Director of Heronsgate House Institute, before it can be destroyed.

The mystery is solved by a series of convenient, and conveniently delayed, recollections. It’s a testament to this series that the death of the heroine’s son produces a reaction that’s stronger but no more heartfelt than usual. Read more about Keating here.