Gangster Joe Valachi is a marked man in the same joint where mob boss Don Vito Genovese is imprisoned and he's forced to co-operate with the DA in exchange for protection.Gangster Joe Valachi is a marked man in the same joint where mob boss Don Vito Genovese is imprisoned and he's forced to co-operate with the DA in exchange for protection.Gangster Joe Valachi is a marked man in the same joint where mob boss Don Vito Genovese is imprisoned and he's forced to co-operate with the DA in exchange for protection.