Dicky got hooked on drugs and had a long rap sheet including an assault on a police officer which at this point even the boxing commission wanted Micky to not allow Dicky to train him anymore. HBO did a documentary of Dicky's life and how drugs ruined him which he watched from prison with other inmates. After watching the documentary he finally understood how far he had fallen and decided to turn his life around through turning back to God.
Meanwhile Micky started putting a string of wins together and got a shot at the second ranked boxer who was getting ready to get a title shot. Quite frankly, it was going to be the first real boxer Micky had fought so very few people besides family and friends thought he’d win.
He went to visit his brother in prison who found out the strategy he was going to use in the fight and he said it wouldn't work and gave Micky something else to try. Micky went with his new trainer's plan and it wasn't working so in the middle of the fight he switched to Dicky's plan and he ended up winning.
Micky was given a chance to fight the champion who had never lost a fight and had knocked out every opponent but one. Dicky got out of prison and showed up at the gym where Micky was training but was told he had to leave because he wasn't allowed to train Micky anymore. Dicky was devastated and left. Micky tracked him down later and said he didn't care what everybody else said that he wanted him in his corner during the championship fight so Dicky took over the training.
They left for London (which was the first time his family had gone anywhere), and after several rounds the referee stopped the fight and Micky won by a TKO. The world was shocked.
By the way the movie called The Fighter became one of very few movies in history where the Academy Awards gave out the "Best Supporting Actor" and "Best Supporting Actress" both in the same film. Christian Bale received the award for "Best Supporting Actor" which he dropped a lot of weight for the role to play a strung-out druggie. It was pretty amazing.