Returning from the Mediterranean with Letty aboard, James comes across Egyptologist Professor Dawson and his daughter Emma, who is clearly ill, adrift in a small boat. The professor has a mysterious item which he keeps in a bag and, learning that they have escaped from a ship carrying lepers, James quarantines them. However a sailor called Jimmy also falls ill. The professor throws the casket that he has been hiding, stolen from a Pharaoh's tomb, overboard upon which Emma recovers but Jimmy dies. Elizabeth discovers not only that Daniel has been cheating on her but that Samuel, who now has married Charlotte, is refusing to let William see his son.