It's 1969. Man is walking on the moon. Nearly a half million young Americans are congregating in upstate New York for Woodstock. Jennifer Lopez is born.
And William Miller is an eleven-year-old kid growing up in San Diego.
He lives with his mother, Elaine, a college professor, and his older sister, Anita. He's precocious—he even skipped two grades—but he has difficulty fitting in. His world is changed, however, when Anita leaves home, entrusting her record collection to young William.
Fast-forward four years.
It's now 1973, and William is a senior in high school. An aspiring rock journalist, William has the opportunity to meet legendary rock critic Lester Bangs, who offers him an assignment covering Black Sabbath. At the concert, William befriends the mysterious Penny Lane, a groupie (ahem, Band Aid), as well as the members of Stillwater, the opening band.
Rolling Stone magazine offers William an assignment to go on the road with Stillwater, which he gladly accepts. Completing the story, however, proves to be more difficult than he has anticipated. The band's enigmatic guitarist and biggest talent, Russell Hammond, repeatedly defers William's request for an interview. Meanwhile, William's growing feelings for Penny are complicated by Russell's romantic relationship with the Band Aid.
Things change in a hurry when Russell permits the sale of Penny to another band in a poker game. A heartbroken Penny follows the band to New York, only to wind up overdosing on Quaaludes. Fortunately, William is there to save the day. After a heart to heart, William escorts Penny to the airport, where she leaves for home.
Following a near-death experience aboard the Stillwater airplane, William finally leaves the tour, heading to the Rolling Stone offices in San Francisco to finish the article. At the suggestion of Lester Bangs, William's completed piece is "honest and unmerciful." Stillwater, however, with Russell at the helm, denies the truth of the story.
Embarrassed, dejected, and alone, William serendipitously runs into Anita, now a flight attendant, in the airport. The two return home together.
Meanwhile, Russell tries to get in contact with Penny. After speaking on the phone, Penny gives Russell what he thinks is her address—but it's actually William's. Russell arrives at William's house, thinking it's Penny's, but he quickly discovers where he is and realizes why Penny sent him there. He tells Rolling Stone the truth and reconciles with William.
Then and there, he finally gives the young journalist the honest, heartfelt interview they both deserve—which ends up making the cover of Rolling Stone.