Kat Ellis (DEBRA MESSING) is in full crisis mode. The neurotic and high-strung customer service rep for Virgin Atlantic has to fly from New York to London for her sister's wedding. She's not looking forward to that since her ex-fiancé, Jeffrey (JEREMY SHEFFIELD), is the best man and she currently doesn't have a boyfriend. As a result, she decides to hire male escort Nick Mercer (DERMOT MULRONEY) to pose as her significant other.
The two meet on the flight over where Kat warns Nick that her family -- mom Bunny (HOLLAND TAYLOR), stepfather Victor (PETER EGAN), half-sister Amy (AMY ADAMS), and cousin TJ (SARAH PARISH), among others -- is an odd bunch, but that doesn't faze the smooth Nick then or when he's finally in their company.
They also meet the groom, Edward Fletcher-Wooten (JACK DAVENPORT), and begin their ruse. Although Kat finds Nick's line of work morally repugnant, she ends up slowly falling for him, and the feeling soon becomes mutual.
As the big day nears and their relationship evolves, Kat and Nick must deal with that as well as some surprise revelations that catch them and others off guard and threaten a number of relationships.