Brennan is 40-years-old going on 14. He still lives at home with his mother Nancy and openly nurtures resentment for his boorish and arrogant younger brother Derek. During a medical convention, Nancy meets Robert, who has his own adult son at home - Dale - and the lonely fifty-somethings embark on a whirlwind romance. Wedding bells peel in record time and Nancy moves in with her new husband with Brennan in tow. The new living arrangements pose a dilemma because for the first time ever, Dale must share his bedroom.