Aaron Green, an ambitious talent scout working for a major record label, is given the daunting task of escorting out-of-control British rock star Aldous Snow to a comeback concert at L.A.'s Greek Theatre. The journey begins in London, where Aaron must coax the hedonistic and unpredictable Aldous through a series of chaotic events, including wild partying and dangerous escapades. Along the way, Aaron's meticulous plans are constantly thwarted by Aldous's erratic behavior and penchant for excessive indulgence, heightening the tension and giving rise to numerous comic situations.

The trip quickly spirals into a whirlwind of debauchery, pushing Aaron to his limits while testing his dedication to his job and his commitment to his girlfriend, Daphne. As Aldous and Aaron navigate through various misadventures across multiple cities, their contrasting personalities begin to clash and intermix. Aaron's growing frustration is compounded by Aldous's emotional turmoil in grappling with his past decisions and addictions. The journey forces both individuals to confront personal issues and reassess their lives, leading to a series of revelations and unexpected bonding moments that profoundly affect their perspectives.