A prologue is merely a introduction; it cannot tell the whole story.
But a intro does tell you what is generally going to happen, that line basically means that there will be some type of internal and external conflict. Which is soon to "mend" itself (Fyi, I watched 2 Romeo and Juliet movies and read the play 3 times, if you have more questions, feel free to ask me)
Also if my first answer doesn't work try "This prologue does not disclose all the juicy details of the story
