Ironhead, a man in his 60s, possesses a unique ability to withstand physical punishment due to his extremely strong iron-like skull. Despite his talent, he struggles with debt and unemployment. After a series of events, Ironhead joins a gang as a debt collector, utilizing his skills to intimidate debtors into paying. However, he soon realizes the gang's true intentions and the harm they cause to vulnerable individuals, including a college girl who is manipulated into selling her naked pictures.
Ironhead's grandson is kidnapped by the gang, prompting him to take action. With the help of his siblings, Iron Crotch and Roar, and their master, they rescue the boy and take down the gang. The gangsters, including the leader, Yon, are arrested, and the girls being exploited are freed.
In the end, Ironhead moves in with his daughter's family and vows to never use his skills for harm again, along with his siblings and master.
1. Ironhead is a man in his 60s with an extremely strong iron-like skull.
2. Ironhead was trained in martial arts by his master along with his brother, Iron Crotch, and sister, Roar.
3. Ironhead's brother, Iron Crotch, specializes in bearing a crotch as strong as a diamond.
4. Ironhead's sister, Roar, has a voice that can end people's lives with a single screech.
5. Ironhead, Iron Crotch, and Roar were praised for their talents when they were young but lost interest as they got older.
6. The three siblings remained mostly unemployed throughout their lives.
7. Ironhead was neck-deep in debt and debt collectors came to his apartment.
8. Ironhead's daughter and grandson visited him and offered help, but he was too proud to accept.
9. Ironhead saw a group of gangsters distributing money and decided to join them.
10. Ironhead met the gang leader, Jai, and his right-hand man, Riker, and begged them to give him a chance.
11. Ironhead was kicked out of the gang, but later got a chance to prove himself by collecting money from a stubborn client.
12. Ironhead used his unique technique to collect money and impressed Jai, who gave him a 30% commission.
13. Riker was jealous of Ironhead and tried to change Jai's mind about him.
14. Ironhead's daughter and son-in-law visited him and found out about his profession, but he lost money in the process.
15. Ironhead's son-in-law was a policeman and arrested a man who had stolen money from his family.
16. Ironhead's family found out about his profession and were disgusted that he was using his training to collect debts.
17. The master and Iron Crotch joined Ironhead in his work as debt collectors.
18. Ironhead was assigned to collect from a young college girl, who agreed to pay by selling her naked pictures.
19. Ironhead felt guilty about what he had done and tried to spend time with his grandson to forget about it.
20. The college girl was manipulated into going into a room with Riker, but another gang member, Ling, tried to retaliate.
21. Ironhead's grandson got into a fight with a girl, and Ironhead took the hit, which made him realize he didn't want to associate with the gang anymore.
22. Ironhead quit his job and tried to make amends with the people he had hurt.
23. Ironhead's grandson was kidnapped by Yon's man, and Ironhead was ready to risk everything to save him.
24. Ironhead's group barged into Yon's gym with guns and rescued the kid.
25. The group was captured, but the SWAT team dropped from the ceiling and arrested the gangsters.
26. Ironhead moved out of his home and went to live with his daughter's family.
27. Ironhead, Iron Crotch, Roar, and their master vowed to never use their skills hastily again.