Though they live fulfilling, independent lives in three different countries, Olivia Segal, Jamie Arias and Annie Aldrich Thomas remain bound to each other by a past tragedy - and by their pact always to be there for each other at times of great need.
The first 'menaces' brought Herbert Sipson, professional blackmailer, to the dock, charged with having demanded 10,000 from a bingo company under threat of bombing their premises.
Barrister Martin Ainsworth is sent to West Berlin by British Intelligence to make contact with his former lover, a suspected Communist agent, and it's up to him to find out the truth and to spot her contacts.
A police officer needs the quickness and guile of a bookmaker, the ingenuity of a psychiatrist and the physical reserves of a Marine, or so it seems to Detective Chief Superintendent Manton, who is called in to investigate a huge bullion robbery and its possible link with the death of a solicitor in a car crash.
Retired headmaster Malcolm Chance and his wife, Frances, have settled down in the quiet village of Ravenswood, where the greatest excitement revolves around the newest production of the local dramatic society.
Professor Alistair Dirke thought himself a reasonable man - he could scarcely acknowledge the suspicion that was beginning to grow in his mind every time he saw his wife Rose with Paul Eckleston .
When Meg Jeacock let out the furnished cottage next to her house she did not care that her new tenant had certain rather sinister characteristics - he'd paid three months' rent in advance.
