Not my problem
(Book)

Aideen's best (and only) friend is pulling away. Her mother's drinking problem is a constant concern. She's running out of diseases to fake so she can skip PE. When she sees her nemesis, overachiever Meabh Kowalski, in the midst of a full-blown meltdown, she sees a problem that-- unlike her own disaster of a life-- seems refreshingly easy to solve. She volunteers to help Meabh escape her crushing pile of extracurriculars ... by pushing Meabh down the stairs. When another student learns about their little scheme and brings Aideen another 'client" who needs her "help" it kicks off a semester of traded favors, ill-advised hijinks, and an unexpected chance at love. -- adapted from jacket