From 1962 to 1964, the Beatles go from unknown Liverpool upstarts to the most successful band in the world. And they do it on the strength of John Lennon and Paul McCartney’s songwriting partnership. Writing together on tour buses and in hotel rooms, they churn out an unprecedented string of hits: “From Me to You,” “She Loves You,” “I Want to Hold Your Hand.” But while Paul is energized by the Beatles’ whirlwind success, John seems exhausted by it. Can their partnership survive the pressures of Beatlemania?