Liu An deployed with twelve other mecha masters to the site of a terrorist attack on a train heading to Heaven Dou City from Shrek City. When they arrived, Liu An saw a unknown battle armour master. They landed a hundred meters away and Liu An asked the man to identify himself. After verifying the man was Zhen Hua, the Divine Blacksmith, Liu An relaxed and let out a deep breath. If Zhen Hua turned out to be hostile, this place would have been his grave. Liu An didn't stop him when he took Tang Wulin with him to Heaven Dou City.
Liu An gave the order to his regiment to search the surroundings of the terrorist attack, but in the end, they never found any trace of hostiles. Not even a single hair to go on. The only evidence of the tragedy, besides the blood and the corpses and destruction, was a small mound of ashes tinged green. The rest of the terrorist’s remains had already been blown away by the wind.
A few days later, Liu An was sent to receive Tang Wulin and Zhen Hua when they arrived at Heaven Dou City's administration offices to give Wulin's statement on the terrorist attack. Liu An esorted them to a private room and questioned Wulin on the events of that day. When Mo Wu came, he gave the statement he had written to him.
Later on, Liu An esorted Tang Wulin back to Shrek Academy. Along the way, he talked to Wulin about being a Mecha Master and exchanged contact information.