Ryu (Akira Kobayashi) sets foot on the Yokohama port with a suitcase filled with 300 thousand dollars. He was sent by a jewelry company in Hong Kong to retrieve a certain diamond that was stolen from them. The "Himalayan Star" is worth couple hundred million yen and unbeknown to Ryu, it now lays in the hands of Aizu (Jo Shishido), the infamous ”Pirate of the Tokyo Bay."
A newly hired daily newspaper writer covering the society beat receives an assignment to cover Tokyo at night by walking and observing it. He gets into the right frame of mind by dressing the part as a vagrant with not a penny to his name. He gets into trouble ending up at the police station slammer overnight. He has no material to write about and, with his assignment unfulfilled, faces a cross editor.