The Notorious Lady is Mary Marlowe (Barbara Bedford), for whose sake her husband Patrick (Lewis Stone) commits murder. Mary manages to save her husband from the gallows, but his reputation is destroyed, so he heads to the diamond mines of Africa to start life all over again. Months later, Mary receives word that Patrick has been killed. Heading to Africa to find out if this is true, she falls in love en route with handsome Anthony Warford (Earl Metcalfe). Inevitably, husband and lover meet in Africa, and it looks as though there's murder in Patrick's eye again. But during a native uprising, Warford saves Patrick's life, prompting the latter's decision to set Mary free to marry her new love.