Heir for Pemberley

Pemberley - 1820... Wickham is determined to obtain 30,000 pounds from Georgina Darcy. Darcy is aware of his enemy's plans. Lydia Wickham is already pregnant but if Darcy can find a way to counter attack with his own child - his sister's pounds will go to his heirs. Elizabeth and Darcy must provide an heir for Pemberley before Wickham decides to contradict!