Elise meets Donald on a flight to Washington, D.C., where he teaches and she edits self-help books. He is dreamy: 6'6 with unflinching green eyes and a proclivity for speaking frankly. Incredibly, they fall in love, get engaged, and start discussing wedding invitations.

And then Elise meets her-Adrienne-Donald’s stunning, leggy ex-fiancee. Adrienne is newly single and planning a move to D.C. Cleavage-baring, half-French, and with a degree from Yale, she seduces men with one flick of her hair. Worst of all, she and Donald have remained good friends since they broke up. Convinced that Adrienne is out to win Donald back, Elise begins stalking both of them obsessively … and starts adding up clues to what looks like a brazen affair.