Watch Back to the Future Part II (1989) HD Full Movie Free on SolarMovie. Watch Back to the Future Part II (1989) online free. After visiting 2015, Marty McFly must repeat his visit to 1955 to prevent disastrous changes to 1985...After visiting 2015, Marty McFly must repeat his visit to 1955 to prevent disastrous changes to 1985...without interfering with his first trip.