This won't end well
(Book)

No new people: that's Annie Mercer's vow. It's bad enough that her boss sabotaged her chemistry career and her best friend tried to cure her with crystals. But after her fianc©♭, Jon, asks for space while he's gallivanting around Paris, Annie decides she needs space too--from everyone. Yet when Harper moves in next door, Annie can't help but train a watchful eye on the glamorous but fragile young woman. And if keeping Harper safe requires teaming up with Mo, a maddeningly optimistic amateur detective, who is she to mind her own business? Soon Annie has let not one but two new people into her life. Then Jon reappears--and he wants her to join him in France. She's pretty sure letting anyone get close won't end well. So she must decide: Is another shot at happiness worth the risk?