Missy Frank, played by Meredith Patterson, is the vivacious, quirky, Broadway tune-loving young fiancee of Ivan Tiggs (Tom Selleck), Shirley Schmidt's ex-husband. She entered the world of Crane, Poole & Schmidt on the arm of her husband-to-be to meet his 'best man', Shirley. During the episode "Live Big", she demonstrated one of her quirks - the near-inability to stop snorting or laughing until someone alarms her with a bad thought:

Missy Frank: "Well, we love children, we plan to have three, all perky. I’m a wonderful housekeeper, I like to cook, these are traditional values I speak of. I’m sexually very… indefatigable."
*And she snorts/laughs. And off she goes*
Shirley Schmidt: "Oh, God. Holocaust, Tsunami. Trent Lott." *And she stops*

In "Ivan the Incorrigible", Missy Tiggs returns to seek Shirley's help in taming the wandering Ivan with a post-nuptial. Shirley writes an iron-clad legal document, perhaps, in part, due to her guilt that Ivan has indeed cheated on Missy - the night before with her. During negotiations, Missy explains her belief in all things positive:

Missy Tiggs: "We live in such a horrible, jaded world these days. No one at all believes in the happy ending anymore. But a big part of me believes that love can be forever. That’s why I love musicals. That’s why I love you. I can’t imagine ever breaking your heart. And I think if you broke my heart my life would be over. But you would never do that to me, would you, Ivan?"
Ivan Tiggs: "Not in a million years."
Missy Tiggs: *With a big smile* "And you’re not getting my Phantom Mask, Mister!"

In "Desperately Seeking Shirley", Missy and Ivan again meet with Shirley, Ivan ready to end the marriage while Missy is blissfully unaware. Shirley tells Ivan he can't get out of his agreement to give Missy much of his wealth and tells Missy the disheartening news that her dream is over. During the ensuing court case, Ivan's counsel, Alan Shore, delights in putting Shirley on the stand in order to rummage through her love life. Missy, through Shirley's examination, explains her take on her marriage:

Missy Tiggs: "I held up my end of the bargain. I was a good wife. I came from a modest background, and this man came in and swept me off my feet. I entered his world and I became accustomed to his lifestyle. Adjusted!"
Ivan Tiggs: "Uh, we were only married nine months."
Missy Tiggs: "I’m a fast adjuster!"

In the end, Missy lost her husband and marriage, but gained half his fortune. Ivan settled by not contesting their post-nup if Shirley would go out to dinner with him at Melvilles - where she turned down Ivan's habit of wooing her once and for all. ("I can't love you anymore.")