本片讲述了约翰·列侬的少年故事。列侬（亚伦·泰勒-约翰逊 Aaron Taylor-Johnson 饰）从小被姨妈Mimi（克里斯汀·斯科特·托马斯 Kristin Scott Thomas 饰）收养，直到15岁才与亲生母亲Julia相认，他的姨妈更和他的母亲展开了对他的争夺。列侬的母亲带着列侬走上了音乐之路，给他买了一把吉他。后来列侬认识了和他差不多年纪的保罗·麦卡特尼（托马斯·桑斯特 Thomas Sangster 饰），保罗矫正了列侬的吉他技法。列侬的生活充满了挣扎和矛盾。直到有一天，列侬的母亲车祸死去，列侬下定决心离开Mimi，离开他从小生长的利物浦，去探求更广阔的天地.....The story of John Lennon's childhood and teenage years from 1944 to 1960, his relationship with his aunt Mimi and his mother Julia -the two dominant women in the first part of his life-, his first meeting with Paul McCartney and George Harrison, their friendship, their love for music and the birth of The Beatles.