The river reveals its secrets... Amateur sleuth Augusta Peel is showing a friend the sights of London when their boat trip on the River Thames is cut short. A body has been found adrift in a rowing boat. The circumstances are puzzling. Scotland Yard takes on the case and Augusta makes some enquiries of her own. But since Detective Inspector Philip Fisher's resignation, she no longer has a contact at the Yard to help her. Could the murder be linked to a series of accidents at a factory? And who was behind an attack on a young woman a few weeks previously? A breakthrough comes when the Yard asks for assistance, but Augusta has already made an enemy who's determined to make life difficult for her. Philip's new detective agency is getting off the ground. And although he's happy to help Augusta, a lady in distress is causing a distraction...