Miles Edgeworth struggles to determine the meaning of his job in relation to finding the truth behind a collection of cases. This is exacerbated when he becomes a target of an inquisition conducted by the Committee for Prosecutorial Excellence intended to weed out and replace prosecutors who are judged to be incompetent or acting inappropriately.

Judge Verity Gavèlle is mysteriously sent to cases that Edgeworth is investigating and attempts to replace him with a younger, less competent prosecutor named Eustace Winner. Edgeworth risks his prosecutor's badge in order to continue his quest for the truth.

In the meantime, he faces a personal conflict when he crosses paths with Eddie Fender, a defense attorney who used to be an assistant to Edgeworth's father Gregory Edgeworth and has taken over the Edgeworth and Co. Law Offices after his death. Miles must decide whether to continue as a prosecutor, or to accept an offer from Fender to follow in his father's footsteps and become a defense attorney.

[Edited from the Ace Attorney Wiki entry.]