The main plot revolves around Gray (Heather Graham), and her newly discovered sexuality. Gray lives with her brother, Sam (Tom Cavanagh), and they are very close. Everything changes when Sam meets a girl named Charlie (Bridget Moynahan). Sam falls in love with Charlie and they marry right away. On the night before the wedding Charlie and Gray share a hotel room, and eventually share a drunken kiss, which causes Gray to begin questioning her own sexuality. She also falls for Charlie in the weeks after the marriage, and begins to accept that she may be gay.
Gray Matters provides examples of:
- Contrived Coincidence: Gray discovers that Julia is gay when she goes to a local gay bar and sees her there.
- I Want My Beloved to Be Happy: Gray eventually realizes that Charlie is deeply in love with Sam, and decides that she doesn't want to ruin their marriage.
- Privacy by Distraction: When it's in the middle of the night and Sam tries to get Gray to go to bed so that he can be alone with Charlie:Sam: Don't you have that big meeting in the morning to get to?Gray: What big meeting?Sam: The big meeting in the morning that you have to get to? That big meeting?Gray: Oh, that big meeting!
- Relative Error: Everyone assumes the relationship between Sam and Gray is romantic, and they are appropriately embarrassed when corrected.
- Queer Romance: Gray and her brother's fiancee Charlie kiss drunkenly on her hen night, realizing that she's a lesbian as a result. Charlie is straight though, and doesn't share Gray's feelings. This isn't a tragedy though, as Gray is accepted by her brother, while accepting her sexuality.
- Sibling Triangle: After sharing a drunken kiss, Gray finds herself falling in love with her brother's fiancée Charlie.
- Transparent Closet: When Grey comes out of the closet to her family, her brother Sam tells her he knew since they were kids and he is okay with it.