A corn vendor, Ken, is selling boiled corns at an unusually low price of 10,000 VND for 3 cobs and is very popular among the locals, including a customer named Mr. Sau. However, it is revealed that Ken has been using bad chemicals and batteries to make the corns soft and sweet quickly, which leads to food poisoning in Mr. Sau. A detective, Vinh Tran, goes undercover and exposes Ken's deceitful methods, arresting him and warning people to beware of cheap street food that may be made unhealthily.
Here are the key facts extracted from the text:
1. Ken sells boiled corns at a price of 10,000 VND for 3 cobs.
2. Ken's corns are boiled using firewood, which makes them soft and delicious.
3. Mr. Sau got food poisoning after eating Ken's corns.
4. Ken is accused of using bad chemicals and batteries to boil his corns.
5. Tram Anh and her friend try to boil corns using firewood but fail to make them as delicious as Ken's.
6. Tram Anh's friend discovers Ken's secret and reports him to the police.
7. The police arrest Ken for using unhealthy methods to boil his corns.
8. Ken is advised to stop selling corns and to change his business methods.
9. The police officer gives advice to the public to beware of cheap street food and to report any suspicious food vendors.
10. Vinh Tran, a detective, helps to solve the case and arrest Ken.