Smart schoolboy Simon Lambertson (17) dates classmate Holly Elman. Her mother, school psychologist Lydia, who defended class rebel Simon against expulsion for repeated mischief, and forced his restaurant-managing father Peter Lambert to agree to therapy he considers grotesquely absurd, faces a dilemma when she learns he's Holly's lover, whom she plans to travel to Latin America with. Deontology-barred from warning Holly, she tries sabotaging the couple and manipulating Simon, while falling in love herself with Peter, who proves a devoted father and brilliant chef. It gets worse when she learns Holly is part of a Don Juan wager and Simon overreacts.