The irreverent yet fact-based tale of a seafaring band of rogue rock and roll deejays whose "pirate radio" captivated and inspired 1960s Britain. Playing the music that rocked a nation and a decade, the group boldly and hilariously defies the government that tries to shut them down.

Broadcasting live 24/7 from an old tanker anchored in the middle of the North Sea (just beyond British jurisdiction), Radio Rock sends out a vibrant and unifying signal to millions across the nation, ranging in age from wide-eyed pre-teens secretly tuning in long past their bedtimes to everyday people in need of a musical pick-me-up. The Radio Rock roster, overseen by unflappable station owner (and ship's captain) Quentin (Bill Nighy), includes a risk-prone American known only as The Count (Philip Seymour Hoffman); mystic deejay royalty Gavin (Rhys Ifans); slyly amorous Dave (Nick Frost); idiosyncratic New Zealander Angus (Rhys Darby); the rarely seen Bob (Ralph Brown); the aptly named Thick Kevin (Tom Brooke); lovelorn Simon (Chris O'Dowd); ladies' magnet Mark (Tom Wisdom); shy Harold (Ike Hamilton); reporter News John (Will Adamsdale); and lesbian ship's cook Felicity (Katherine Parkinson).

One night in 1966, Quentin's teenaged godson Carl (Tom Sturridge) comes aboard. While Carl harbors romantic aspirations that he hopes will be fulfilled during one of the biweekly visits by Radio Rock's prettiest fans, he also hopes to find out more about his long-absent father...

As the ship sails on and rocks out, what Carl and the freewheeling, free-loving Radio Rock gang don't know is that back in London, landlocked government minister Dormandy (Kenneth Branagh) has embarked on a vehement crusade to silence their signal—permanently. To stay afloat and keep their devoted audience plugged in, the crew will have to band together and trust in the power of music like never before.