Nothing to See Here by Kevin Wilson 

Lillian and Madison were unlikely roommates and yet inseparable friends at their elite boarding school. But then Lillian had to leave the school unexpectedly in the wake of a scandal and they’ve barely spoken since. Until now, when Lillian gets a letter from Madison pleading for her help.

Madison’s twin stepkids are moving in with her family and she wants Lillian to be their caretaker… Read more.