Daphne notices a ladybug in her bathroom. She wonders if they’ll make her lucky, then masturbates while her younger son, Tyler, plays with toys and her older son, Kyle, is still at school. She reminisces on sex, love, and her relationship with her husband, Craig. 

A week later, she notices increasing amounts of ladybugs but doesn’t want to kill any of them. Daphne is pregnant with her third child and is struggling to keep up with the housework. Craig notices and offers for his mother to come help.

The next day, Daphne’s mother-in-law, Carroll, arrives with a nanny named Nat. Over the next few weeks, Nat takes care of everything. She cooks, cleans, and is particularly good with the children, but kills all the ladybugs.

While staring at her body in the mirror, desperate to meet her unborn child, Daphne’s water breaks. She gives birth two months early to another son, Adam.

Daphne arrives home with the new baby and is immediately grateful for all Nat’s help. The night she gets home, Nat tells the family her husband calls her Mrs. Covet because she always orders what her husband orders at restaurants. Daphne and Craig start calling Nat Mrs. Covet. To take care of the baby in the night, Nat moves into the house.

One morning, Daphne finds Nat trying to move the baby’s crib into her room. Daphne demands she move it back and Nat tells Daphne she spoils her children. The stop fighting only when Nat breaks down, telling Daphne she’s fallen in love with her family.

In the middle of the night, Daphne hears singing. She finds Nat has taken the baby from her room and is laying with Adam. Daphne is furious and takes the baby back. Nat leaves for the weekend.

On Monday, Nat returns. When Daphne leaves the baby with Nat to go pick up the older boys from school, Nat and the baby aren’t home when they return.

Panicking, Daphne recalls how her baby sister died. As a child, she cast spells on her infant sister to disappear. Then, her sister died in her sleep.

Daphne and Craig can’t get in touch with Nat and call the police. By morning, the police have found Nat and the baby in Florida. The family travels to Florida to retrieve Adam. On the news, they see Mrs. Covet has been arrested for kidnapping.