James Hunt, a brash and self-confident individual, and Niki Lauda, a cool and calculating technical genius who relies on practice and precision, are exceptional racing car drivers who first develop a fierce rivalry in 1970 at a Formula Three race in London, when both their cars spin before Hunt wins the race. Lauda takes a large bank loan from Austria's Raiffeisen Bank to buy his way into the BRM Formula One team, meeting teammate Clay Regazzoni for the first time. Meanwhile, Hesketh Racing, the fledgling racing team Hunt drives for, enters Formula One. Lauda then joins Scuderia Ferrari with Regazzoni and wins his first championship in 1975. Hesketh closes down after failing to secure a sponsor, but Hunt joins the McLaren team. During this time, Hunt marries supermodel Suzy Miller, while Lauda develops a relationship with German socialite Marlene Knaus.

The 1976 season starts with Lauda dominating the first two races while Hunt struggles to catch up. Hunt wins the Spanish Grand Prix, but is disqualified after a post-race inspection results in a ruling that the width of his car greater than permitted. Struggling to comply with F1 rules, McLaren suffers a series of racing setbacks, and Hunt's situation is further exacerbated when Suzy starts a relationship with actor Richard Burton. Following his divorce, Hunt regains his competitive spirit and, when his disqualification in Spain is overturned, the restored points put him into championship contention. Lauda marries Marlene in a private ceremony but begins to have concerns about the effects of his newfound happiness, worrying that he has become vulnerable as a racer, as he now has something to lose.