Would-be politician Sir Hugo Boycott and his wife Madeleine have an unhappy marriage. Madeleine is aware that Hugo is a serial philanderer, and their problems are exacerbated when she fails to produce the heir he wants.
A charming, tender-hearted American boy who adores his mother and promised his dying father that he would always take care of her, turns out to be the long-lost heir to a British fortune and is sent to live with the cold, unsentimental lord who oversees the trust.
Eustace Ede, the unhinged brother of Lady Magda Ware, is discovered drowned in the lake of her country house. While most assume it to have been suicide, a detective inspector's persistence finally leads to the arrest of Magda's husband, Sir Hubert Ware. The subsequent murder trial turns into a...