There are no confirmed details about this sequel. One rumor is that it may
involve the return of Nick Van Owen (Vaughn), although in what capacity isn't
known. The last we saw his character, he was handling the Lost World problem in
San Diego. If there's any truth to that, it suggests the story may next pick up,
not on Isla Sorna, but on a much bigger island... North America (since this is
what many fans would love to see, however, it's possible the whole Vince Vaughn
thing could be wishful thinking, hoping to spur just such a film).
Anderson Jones of E!
Online reports that the fourth movie may "pretend Jurassic Park III never happened." I wouldn't read
that the wrong way... they probably just mean there would be no references to
that film's events/characters. One detail that was recently announced
about this project is that it will not take place in a jungle like the first
three movies. There are also rumors that Keira Knightley's character would
actually be Lex Murphy, the grown-up granddaughter of Jurassic Park founder John
Hammond who was the little girl in the first movie. Knightley is slightly*
young (she would have been 8 in 1993), but she's not far off. Please note this
rumor is unconfirmed.