Danny (Rob Lowe) doesn't want to get serious. Debbie (Demi Moore) doesn't want to get used. But after a casual, one-night stand, the unthinkable happens - they want to see each other again. It's the start of an intense relationship that irritates Danny's rowdy friend (Belushi) and Debbie's cynical flatmate (Perkins). But Danny and Debbie wind up living together and, amidst the drudgery of domestic life, they discover that making love is easy, saying 'I love you' is more difficult and being in love is the hardest of all.