Agatha Christie's Seven Dials Mystery

When Gerry Wade sleeps in and is late for breakfast, his friends find that he has a very good reason - he's been murdered. Lady Eileen Brent, known to her friends as Bundle and in whose bed Wade died, returns home and decides to investigate. When a second man is killed, he mentions something about " ...seven dials...tell Jimmy Thesiger..." but Thesiger has no idea what he was talking about. What they learn is of the existence of a secret society and of a hugely valuable formula for making a specialized form of steel. But who exactly is behind the two murders and why were they killed?