Romeo's killing of Tybalt is the turning point of the play-the point when something happens that will turn the action toward either a happy ending or a tragic one. What actions does the killing set in motion, with possible tragic consequences ?

The killing of Tybalt means dire consequences for Romeo. The Prince had threatened death to whomever disturbs the peace in Verona streets. We know Romeo will be killed or at best banished for killing Tybalt. There will also be retribution called by both families for the death of their kinsmen. Romeo and Juliet will find it increasingly harder to be together.