Knightsbridge (S01E02)

Richard Mayhew finds himself trapped in a strange parallel realm hidden beneath London, yearning to return to his former life. His best hope lies in locating Door and the Marquis, who are on their way to the Floating Market to recruit a bodyguard for Door, as they are pursued by the dangerous duo, Croup and Vandemar. However, Richard soon realizes that he also needs someone to safeguard him on his perilous journey.