The film's events have Lisa taking notice of withdrawn student Jimmy Roy, listening in on him as he recited a poem to himself while pacing, being left in awe at Jimmy's natural ability. Seeing potential in Jimmy, Lisa asked his babysitter Becca (who was largely responsible for taking care of him due to his father working often) to write down any poems he came up with and to tell her about them.
Lisa also began to take a special interest in Jimmy, believing him to be a prodigy in need of having his talent nurtured. While initially on good terms with Becca, though, Lisa came to believe that Becca (in her mind) treated Jimmy like a baby and didn't realize the full extent of his talent, encouraging Jimmy not to let her demean him and giving him her cell phone number to call her whenever a poem came into his head. All the while, Lisa was presenting Jimmy's poems to her poetry class, where they received praise and caught the attention of the class's teacher Simon.
The film's events also show that Lisa's intense devotion to Jimmy was causing tension in her already estranged marriage to her husband Grant, with Lisa at one point leaving Grant in the middle of a moment of intimacy to take a call from Jimmy. She was also shown to be estranged from her teenage children, Josh and Lainie, disapproving of Josh's desire to enlist in the Marines after high school rather than go to college and believing both of her children lacked curiousity and intellect, with Lainie blasting her mother during a pool party at their house for her self-righteous attitude and for not appreciating how she was getting straight A's in school.
After several failed attempts to contact Jimmy's father Nikhil, Lisa met with him at the nightclub he owned, telling him how she believed his son had a gift that needed to be nurtured (even comparing Jimmy to Mozart) while claiming Becca was a bad influence for Jimmy, citing how she was frequently late in picking up and dropping off Jimmy. In response, Nikhil revealed that while he was happy that Jimmy was intelligent, he wanted his son to have a normal and practical life. After Nikhil revealed he intended to fire Becca, Lisa happily volunteered to take care of Jimmy after school for a few hours after school each day, with Nikhil accepting. But when told by Lisa that she wanted to take Jimmy to a poetry reading in Manhattan, Nikhil instead informed Lisa that Jimmy had baseball practice he had to go to.
While she initially appeared to acquiesce to Nikhil's request, Lisa instead began to turn heel by taking Jimmy to the poetry reading instead of baseball practice, telling Richard (the father of a classmate of Jimmy's who took him to practice) that Jimmy was feeling sick and that Nikhil asked Lisa to take him home with her. At the poetry reading, Jimmy read two of his poems, which were well-received by the audience (which included Simon). When asked by an audience member if he was the writer of the poems, Lisa responded that he was, with Lisa becoming emotional and crying in the bathroom after the Q&A session. Later on, when Amy tried to talk to Simon about Jimmy's poems, Simon asked Lisa to withdraw from the class, revealing his disapproval of Lisa presenting Jimmy's work as her own and accusing her of exploiting Jimmy for her own gain (an accusation Lisa firmly denied) before chastising her for not being a true artist.
After the reading, Lisa took Jimmy home with her and had him sleep on the couch, and when she went upstairs to go to bed herself, Grant asked her if she was proud of their children due to Josh's belief that she was disappointed in them, with Lisa assuring her husband that she didn't feel that way. The next day at school, Lisa became concerned when Jimmy was missing from school, calling him on his cell phone to ask where he was. Lisa later got a call back from Nikhil, blasting her for taking Jimmy to the poetry reading behind his back and revealing to her that he intended to enroll Jimmy in a new kindergarten. At that, Lisa fully turned heel by following Nikhil as he dropped Jimmy off at his new school, talking to him at recess and convincing him to come with her to go swimming. After that, Lisa took them to a hotel near a beach up north, where Lisa became emotional over Jimmy coming up with a poem.
Soon after Lisa and Jimmy returned to their hotel room, however, Jimmy revealed that he was aware of the true nature of the "trip" when he locked Lisa in the bathroom while she was showering. As Lisa attempted to convince Jimmy to unlock the door, she revealed the full extent of her plans: to take Jimmy across the border to Canada, where she planned to have Jimmy read his poetry before ultimately publishing them in a book. However, upon hearing Jimmy attempting to call the police to report her for kidnapping him, she reminded him that he had to dial 911 to call the police. The villainess also angrily proclaimed that the world would "erase" Jimmy and that there was no place in the world for people like him, while also voicing that he would grow up to become "a shadow" like her; indicating that Lisa's devotion to and eventual abduction of Jimmy was motivated by her deep unsatisfaction with her own life.
Despite her dismay over her plans being derailed, Lisa helped Jimmy call for help by telling him the address of the hotel they were at, and remained solemn after convincing Jimmy to let her out of the bathroom so she could put her clothes back on before the police arrived. After getting dressed, Lisa held hands with Jimmy before the police arrived, with Lisa being arrested (off-screen) on kidnapping charges.