A devilishly handsome detective from Scotland Yard, Simon Hunt, teams up with Castle and Beckett to find the person responsible for the murder of his friend's daughter. Enter Nigel Wyndham, the Deputy General at the British Consulate whom Castle and Beckett suspect is up to more than just ambassadorial balls and diplomatic luncheons. Meanwhile, Lanie convinces Beckett that she needs to make a move on Castle before it is too late.