Hail Caesar (1994)

Caesar is having a hard time dividing his time between his band and his rich girlfriend, Buffer. Buffer's dad doesn't like Ceasar for her. He called in Caesar to make a bet. If Caesar gets to make a hundred thousand dollars within six months, he can have Buffer but if he does not, he won't see her forever. How can Ceasar win the bet if what he only knows is jam with his band mates?