Minnie and her sister Anna were orphaned and each sent to live with different relatives. Minnie went to Texas where her guardian-uncle was a successful businessman and owned big property. When he died, he left her a nice home worth a lot of money.
Minnie meets Holmes in Boston while he's traveling on business under the alias Henry Gordon. When he learns of her inheritance, he begins to woo her…and succeeds. By the time Emeline Cigrand's gone, Minnie announces that she's moved to Chicago (likely because of Holmes).
He pops the question, and Minnie's sister Anna's urges her to slow down. Everything seems to be moving way, way too fast.
And it is moving fast, because Holmes has an agenda. He persuades Minnie to transfer the deed of her dead uncle's Texas property to a man named Alexander Bond, an alias for Holmes himself. Minnie also doesn't know that Holmes is legally married to two other women, Clara Lovering and Myrta Belknap. Holmes and Minnie wed secretly, but there's no record of their marriage in the registry of Cook County, Illinois.
As with most of Holmes' women, Minnie grows jealous of all the attention her husband receives from women who enter the store. Holmes wants to get rid of Minnie, so he puts her up in an apartment close by (but yet far enough away). Minnie likes the idea of a sunny apartment, as opposed to the dark hotel, so she's fine with it. Holmes invites Minnie's sister Anna to spend the summer in Chicago. The three of them visit the fair and have a wonderful time.
But then it's time to move on. Holmes kills Anna…and then brings Minnie back to the hotel to finish her off, too.