What event does the opening passage of act 3 hint at or foreshadow in romeo and Juliet?

"Two households, both alike in dignity"

~Two homes, similar in ideas

"In fair Verona, where we lay our scene, "

~In Verona, Italy, where our scene takes place

"From ancient grudge break to new mutiny,"

~From old problems new issues form

"Where civil blood makes civil hands unclean."

~Where spilling noble blood ruins noble reputations

"From forth the fatal loins of these two foes "

~Coming from these two rivals

"A pair of star-cross'd lovers take their life;"

~Two lovers have a sealed fate for their lives.

"Whole misadventured piteous overthrows"

~A heartbreaking plot takes place

"Do with their death bury their parents' strife."

~Their deaths will ends their parent's argument

" The fearful passage of their death-mark'd love,"

~The shaky story of their doomed love

" And the continuance of their parents' rage,"

~Along with their parents' ongoing anger

"Which, but their children's end, nought could remove, "

~Which nothing but their child's death could not undue

" Is now the two hours' traffic of our stage; "

~Is the 2 hour story presented on our stage

"The which if you with patient ears attend,"

~To what those interested will hear

" What here shall miss, our toil shall strive to mend."

~What you don't understand, our production will explain.