A gangster named Miyamoto gets out of prison after serving three years for a diamond heist. He hid the diamonds before being caught and his partner was injured and is now disabled and running a street cart. The partner has a sister who is (or becomes) the Underworld Beauty.
When Miyamoto gets out he wants to sell the diamonds and give the money to his partner. So he goes to the boss who has contact. A deal is made, but during the sale it goes south and the disabled partner swallows the diamonds and jumps off a roof. How are the gangsters going to get the diamonds back? Well, I'm not going to spoil that for you, but they do, and there are double-crosses, greed, and honor at stake.
A pretty solid Yakuza film, and an early enough Suzuki that it has a straight narrative and shows some excellent camera work.