Roger Ackroyd knew too much. He knew that the woman he loved had poisoned her brutal first husband. He suspected also that someone had been blackmailing her. Then, tragically, came the news that she had taken her own life with a drug overdose. But the evening post brought Roger one last fatal scrap of information. Unfortunately, before he could finish reading the letter, he was stabbed to death.

When the recently orphaned Anne Beddingfield moves to London to live with her late father's solicitor and his wife, she is ready for adventure to find her, and find her it most certainly does.

While waiting for the tube after a failed job interview, Anne witnesses a man fall off the Underground platform onto the rails. The police determine the man's death to be "accidental." But the examining doctor fortuitously leaves behind a rather curious

...

A prominent attorney's wife dies of cyanide poisoning; but when he attempts to recreate the crime scene, he, too, is poisoned. The heiress to the estate is the prime suspect, but there have been apparent attempts on her life also.