Feeling undervalued by his friends, Gunn submits to a procedure at the hands of Wolfram & Hart's Medical Department that enhances his mind with a comprehensive understanding of the law (and Gilbert & Sullivan, to help improve his voice and diction), making him the only member of Angel's team who can work inside the system seamlessly (cf. "Conviction"). When his mental abilities begin to diminish, Gunn, fearful of losing his new talents and respect, makes a pact with Dr Sparrow and gets a permanent upgrade in exchange for signing to release an ancient curio stuck in customs. When this curio results in the death of Fred and the resurrection of Illyria (cf. "A Hole in the World"), a guilt-ridden Gunn willingly offers himself to take Lindsey McDonald's place in a hell dimension in order to get information on how to stop the Senior Partners (cf. "Underneath"). While the team have no clue how to free him, Illyria saves Gunn with ease. He then returns to the fold, changed and seeking redemption for his sins. In the show's finale "Not Fade Away", he slays Senator Helen Brucker, one of the members of the Circle of the Black Thorn, but is seriously injured in the process. While prepearing for one last fight against the army of the Senior Partners, Illyria states that he has only minutes to live, and the outcome of his survival is left unanswered by the show.