El amor está en el aire, pero ¿qué significa eso para Greg Heffley? Un baile de San Valentín en la escuela de Greg ha puesto su mundo patas arriba. Mientras Greg se apresura a encontrar una cita, le preocupa quedarse afuera en el frío en la gran noche.
Greg Heffley is not willing to be the odd man out. A dance at Greg's middle school has everyone scrambling to find a partner, and Greg is determined not to be left by the wayside. So he concocts a desperate plan to find someone—anyone!—to go with on the big night. But Greg's schemes go hilariously awry, and his only option is to attend the dance with his best friend, Rowley Jefferson, and a female classmate as a "group of friends." But the night is long, and anything can happen along the way. Who will arrive at the dance triumphantly, and who will end up being the third wheel?