It came from the desert
In San Francisco, talk to Dr. Wong Yi Tze, the Shi's doctor (in the right area). Ask him if he has a job for you, and he will tell you about the ants near San Francisco that could soon become a problem. You will have to go to the nearest ant nest and kill all the ants there. Dr. Wong marks the location on your map (it's approximately four squares north-east of San Francisco).
Though the ants may seem like a weak opponent, this quest is more difficult than it sounds. There are around 40 ants in the lair and they might all rush you right after you enter the location. Low level characters can die there quickly, and even more experienced characters may have a problem. After you kill all ants in the lair, go back to Dr. Wong to get your reward.
This quest is repeatable with some waiting time between opportunities (75 RT minutes).
Note: This quest uses ad-hoc created locations. Do not use them as storage facility, because they will be automatically removed by server after some time.