Frasier counsels a listener, Gretchen (voice of Glenne Headley), when she fears that her fencing instructor husband, Gunnar (guest star Brian Cousins), is having an affair with one of his students. Frasier concludes from the thrust of Gretchen's story that his sister-in-law, Maris, is the swordman's student/girlfriend. Both Martin and Roz advice Frasier to stay out of it, but he's determined to help Niles fight for his marriage.