S.D.U. - Mission in Mission(飞虎雄师之极道战士)

The story follows Hunter and Yat, two new hot shot recruits, who under the watchful eye of their commanding officer, Yuk Pai, rise quickly through the ranks, enduring much mental and physical hardship along the way. Their new found skills are put to the test when renegade SDU member returns from seclusion in Thailand to wreak havoc on Hong Kong and the SDU's most secret missions.