Molly is flying home to Chicago for her mom's wedding and tells her family she is bringing a "Mystery Man." When she discovers her Mystery Man has a Mystery Wife, she dumps him curbside. In shock, she runs into childhood friend Josh who is flying to the same event. Josh convinces a reluctant Molly to play fiancée for a few days. As the lie grows, the two boisterous families begin to plan what is really a phony wedding and somewhere in the chaos Molly and Josh may actually be falling for each other.