In 1975, San Fernando Valley teen Joan Larkin reinvents herself as Joan Jett, a guitarist who wants to form an all-girl punk band. She pitches the idea to a sleazy manager, Kim Fowley, who pairs her with a drummer and then searches for a face: he finds Cherie Currie, at 15 the perfect jailbait image for his purpose; by luck, she can sing. Two others round out the band, "The Runaways." Fowley books a tour, signs them to Mercury Records, and packs them off to crowds in Japan. Seeds of conflict...