Kassie O'Callaghan's meticulous plans to divorce her emotionally abusive husband, Mike, and move in with Chris, a younger man she met five years ago on a solo vacation in Venice, are disrupted when she finds out Mike has chronic kidney disease--something he's concealed from her for years. Once again, she postpones her path to freedom--at least, until she pokes around his pajama drawer and discovers his illness is the least of his deceits.

But Kassie is no angel, either. As she struggles to justify her own indiscretions, the secret lives she and Mike have led collide head-on, revealing a tangled web of sex, lies, and DNA. Still, mindful of her vows, Kassie commits to helping her husband find an organ donor. In the process, she uncovers a life-changing secret. Problem is, if she reveals it, her own immorality will be exposed, which means she has an impossible decision to make: Whose life will she save--her husband's or her own?