The story of Rita Hayworth and Shawshank Redemption begins in 1948 when Andy Dufresne arrives at Shawshank prison. In contrast to most other convicts, he's not a hardened criminal but a soft-spoken banker, convicted of killing his wife and her lover. Like everyone in Shawshank, he claims to be innocent. Like most newcomers, Andy gets in trouble with the sisters.
They are a gang of sodomites led by Bogs Diamond that gang up on anyone they feel they can handle, and Andy is no exception. Not until much later does he escape their attentions. Red, the narrator of the story, is known as the guy who can get stuff. His ability to deliver contraband of almost any type into Shawshank makes him somewhat of a celebrity among prisoners, and it's also the reason that Andy approaches him. Andy's hobby outside the walls was rock-carving, and now he has immense amounts of free time on his hands, so he asks Red to get him a rock hammer. He uses this to shape small rocks he finds in the exercise yard into small sculptures. The next item he orders from Red is a large poster of Rita Hayworth.
When taking the order, Red reflects that Andy is excited like a teenager just for ordering a pin-up poster, but doesn't think more of it then. One spring day, Andy and Red and some other prisoners are tarring a roof when Andy overhears a guard griping over the amount of tax he will have to pay on an inheritance he has just gotten from a run-away brother. Andy approaches him (almost getting thrown off the roof in the process) and tells him that there are legal ways to avoid taxation. He offers to help him with all the necessary paperwork for the operation, in exchange for some beer for himself and the other prisoners on the roof. This is the beginning of a long stretch of economic work for Andy. More and more of the screws discover that they can use him for tax returns, loan applications, and other things like that.
In return for his help, he gets protection from the sisters and is allowed to stay alone in his cell instead of having a cellmate like most other prisoners. For a short period, he shares a cell with an Indian called Normaden, but he soon leaves again. He keeps complaining about the draught in the cell while there. When Brooksie, the previous prison librarian, is paroled, Andy takes over the prison library and starts to send applications to the state senate for money for books. For a long time, he gets no response to his weekly letters. Finally, he gets some money. Instead of ceasing his letter writing (like the senate probably hoped), he starts writing twice as often.
His diligent work makes the library very good, and he also helps a number of prisoners catch up on their studies, preparing them for life outside. The warden of Shawshank, Norton, also realizes that a man of Andy's skills is useful. He has started a program called "Inside-Out" where convicts do work outside the prison for very low wages. Normal companies outside can't compete with the cost of Inside-Out workers, so sometimes they offer Norton bribes not to bid for contracts. This cash has to be laundered somehow, and here Andy is useful. One day, Andy hears from another prisoner about someone having bragged about killing a rich golfer and some hot-shot bankers wife, and then getting the banker jailed for it.
Hearing this, Andy of course sees the possibility of a new trial since.