In Paris of the not-too-distant future, a mysterious new disease named STBO is killing young people who make love without emotional involvement. A serum has been developed, but it is locked away in an office block, out of the reach of those who need it most. An United States of America woman blackmails two aging crooks, Marc and Hans, into stealing the STBO serum. Marc recruits Alex, a rebellious teenager whose father worked for him before getting himself killed. Although Alex has a girlfriend, Lise, he ends up falling for Marc’s young lover, Anna...