Just as she is about to return home to Northern California for her brother's wedding, Marni learns from her mother that her brother Will is marrying Joanna, her high school arch nemesis. Marni is horrified. Why would her brother marry the one girl from high school who made her life miserable all those years? Making matters worse, Marni's entire family, including her father, little brother, and even Grandma Bunny welcome Joanna into their family like she's an angel, and the bride-to-be herself acts as though nothing ever happened between them. Marni realizes it's up to her to let her family find out Joanna's true colors before it's too late.