Pitched Battle of the Great Wall Train - Part 2.The Tigers capture humans to power their Great Wall Train to cure HighRoller's toothache by using the Great Wall Train's ability to travel through time. First Squad heads to the Rocky Desert to save them and dentist Wu Sung (who has also been captured while gathering ingredients to his toothpaste). When the train moves, everyone (including First Squad) turn old and Lin Chung fell off the train and they need to figure out how to turn him back to normal.