Denise is the new assistant manager of Stuart's comic book store.
Being into comic books, Denise is intelligent enough to know what kinds of comics certain people like.
When the comic book store suddenly starts to become popular, which Sheldon isn't too thrilled about, Stuart hires Denise as his new assistant manager. Sheldon isn't crazy about her initially, but starts to warm up to her as he discovers she knows what kinds of comic books he prefers. After hearing all about her from Sheldon, Amy barges into the comic book store and asks Denise for advice on comic books.
As Sheldon and Amy’s wedding approaches, Stuart asks Denise to come to the wedding with him. She is hesitant, until she hears that Mark Hamill is going to be at the wedding too. Stuart buys her a dress, and they sit together, and he impresses her by revealing that he knows more about Star Wars than Mark Hamill.
Early on in the twelfth season, Stuart and Denise begin to develop a relationship, and eventually, they move in together.