Complex sentence: Over the next several days, various instances of paranormal disturbance occur, most notably when Christine and Nancy are attacked one night by an unseen figure behind their door; the activity culminates one night while Roger is away in Florida.
Split into simpler sentences: Over the next several days, various instances of paranormal disturbance occur, most notably when Christine and Nancy are attacked one night by an unseen figure. The activity culminates one night while Roger is away in Florida.