Mr. Frid works as a tutor to Louisa and Titus in the Iredale household in 1919 as a matter of loyalty. When Sir Ivor Creevy-Thorne finds out Frid was let go from his former employers because of missing funds, Sir Ivor uses the information to get Frid to do his bidding.
Frid tries to keep Louisa, Titus and Jo busy so he can move about freely.
When Joshua receives a note from Nicholas Romanov stating Frid is a spy for Sir Ivor, Joshua promptly fires Frid from his employment.
Titus discovers Frid took the real canister of poison and placed it in Sir Ivor's cellar.