Commitment to a goal is a key part of fiction. The main character will stop at nothing to reach that goal which might be clear from the beginning or unfold over time. It might multiply or narrow down, and seem unattainable at times. The protagonist may even lose sight of it, but her/his commitment to reaching it will fuel the story especially as problems arise and challenge the desired outcome.
The Lord of the Rings trilogy is one story in particular that comes to mind when I think of an intense and undying commitment to a goal.