After the training, LI is assigned to be supervised by YAN in Team B. The Immigration Department has recently arrested some illegal immigrants with fake documents. The ICAC investigate the case and they suspect that some senior officers have been bribed and the only clue is the informant called PING. With careful examination, the TSD finds that the chop on the fake documents carries the number 8533. However it is no longer valid. Now there are only five senior officers who can handle the chop. PING is being followed but he manages to escape for LI's carelessness. LIN comes across a poor couple. The husband is paralyzed and the wife has recently come from Mainland China to look after the husband. She is bearing a baby. LIN tries to help them by applying social security for them. She is shocked to see that the chop number is 8533 in the travel document.