Set in the early 1960s, the story follows a young and rebellious artist named Stuart Sutcliffe, who becomes the original bassist for a burgeoning band destined to become one of the world's biggest musical acts. Encouraged by his best friend, John Lennon, Sutcliffe puts aside his artistic pursuits for a life of music, despite having little experience. Alongside Lennon, and other future legends, Paul McCartney, George Harrison, and Pete Best, they head to Hamburg, Germany. There, amidst the city's vibrant music scene, they begin their journey, playing long hours in seedy clubs, honing their skills, and defining their sound. The band's time in Hamburg proves to be a critical phase, filled with music, camaraderie, and the development of their identity.

Amidst this backdrop of transformation and ambition, Sutcliffe finds himself torn between two worlds. He falls deeply in love with a local photographer named Astrid Kirchherr, whose avant-garde influences and understanding of the band's potential impact both their style and Sutcliffe's personal journey. Her presence introduces a crossroads for Sutcliffe, challenging him to choose between his love for music and the possibility of a life as a painter. This internal and external struggle plays out as the band inches closer to their breakthrough, with friendships tested and personal identities questioned in the face of looming fame and the pressures it brings.