The Perfect Roommate by Minka Kent

"She's my roommate. I know how she takes her tea, how she organizes her closet. I know when she goes to bed each night, what she eats for breakfast, the passcode on her phone. I know she calls her mother on Mondays, takes barre on Thursdays, and meets her friends for drinks on Fridays. But more important than any of that ... I know what she did."--Publisher's description.