Back to the Future
The situation in 1955 is complicated when Marty meets his own parents as teenagers. When he helps his father, he accidentally changes the events that lead to his parents becoming a couple. Marty's teenage mother becomes interested in Marty instead of Marty's father, George. With the help of the Doc of 1955, Marty tries to undo the damage he has done, and make his mother fall in love with his father. If he can get his parents back together, he has very little time to get back to the car to use the lightning strike to take the time machine and him (Marty) back to the future (i.e. 1985).