It's 1970. Janis Joplin, The Grateful Dead and The Band are singing their way across Canada on a train full of booze, drugs and fellow rockers. Yep, as subjects for music documentaries go, this one's a bit of a gift. There's controversy, too: the travelling festival attracted mass protests because admission wasn't free.
Footage of the enraged demonstrators casts a revealing light on the idealistic mood of the times, while recent interviews with organisers and surviving performers reinforce the contrast with the modern day. The performances steal the show, though, as living legends jam deliriously with each other into the night.
The road doc format's nothing new, but it preserves such a brief, precious moment in rock history that it'll have fans captivated.