Kamikaze taxi

A young foot soldier in the yakuza seeks revenge when his prostitute girlfriend dies after a session with a high-ranking Japanese politician with a taste for torture. He sets out on a 'kamikaze' mission to kill his bosses and the politician; along the way, he acquires the aid of a taxi driver who has recently returned to Japan after living in South America for several decades and is struggling to cope with poverty and the prejudices of native-born Japanese.