Deputy sheriff Steve Walsh and his partner encounter a trio of young people in Washington between Shelton and Aberdeen. After being taken hostage when the girl, Bobbie, produces a gun, the two deputies are forced by their captors into rural Mason County forests as the group flees an ever-growing search party. Bobbie later tries to seduce Walsh - twice her age - who resists. One of her companions, Roy, tries to push Walsh off a cliff, but plummets to his own death instead.
When the search party comes to Walsh's rescue, Frank, the other captor, accuses Walsh of improper relations with Bobbie, who is a minor. Before the matter can be resolved, all realize that Frank's carelessly tossed cigarette has set the forest ablaze, threatening the town.
Walsh leads an evacuation of the townspeople and herds them aboard a train that leads across a bridge to safety. Frank, trying to flee, falls from the trestle and is killed. Steve tells Bobbie that she is special to him and professes his love by kissing her.