Two years ago, Wang Fei was a typical middle school student - an aspiring fashionista, who enjoyed Korean movies and hanging out with friends.

Fast forward to today, and the 20-year old police officer at the Mukang border checkpoint in Mangshi city, Yunnan province, has taken a crash course in drug law enforcement, covering everything from vehicle inspections to apprehending suspects.

The worst part of her job used to be performing cavity searches and extracting drugs swallowed by "mules".

"The first time I did one, I couldn't eat for two days. I even vomited several times a few days later. I never thought I would be put on the frontline and expected to do such a tough job just a few months after being recruited," she said. "I asked myself some tough questions and even thought about quitting, but the thought of the urgent cases at Mukang encouraged me to continue with my 'mission'."

Wang's role model is Su Dan, a former officer at the checkpoint who seized 15 kilograms of drugs during her first year in the force.

"I trained harder and accepted tougher assignments after I discovered what my predecessors had been through and the things they achieved. Now, I'm capable of disassembling a truck for a drug examination," she said.

"The most difficult of part of my job isn't limited to drug inspections anymore. I could hardly bear the moment last year when I had to arrest a drug-trafficking mother, who had her child with her. She knelt and begged me to let her go because she was only carrying a small amount of heroin, and because her child was so young. I had to arrest her, though. If I hadn't, more families could have been destroyed by drugs."