Serge Pilardosse has just turned 60. He's worked since he was 16, never had a day off work, never been sick. But the time has come to retire and to claim his pension. That's when disillusion sets in: some of his employers have forgotten to declare him and he can't claim what's owing to him. Encouraged by Catherine, his wife, he gets on his old motorbike from the 1970s. "Mammut" is its name, and it gave him his nickname. Man and bike set off to find his payslips. During his adventure, he rediscovers his past and his quest to locate administrative documents soon becomes of secondary importance.