A privileged and impulsive young man attempts to escape mandatory service in his nation's army so he could study abroad with his girlfriend.

The fourth addition to the franchise sees the return of the army boys including Sergeant Ong, Lobang, Ken Chow and Aloysius, joined by a new female officer, as they are called back for in-camp training under the Armoured Formation of the Singapore Armed Forces. Hilarious situations happen when they are back training together and their military roles reversed. Their brotherhood is also put to the test when new enemy threats arise.

After realising his foolishness in malingering, Ken returns to Tekong to continue his Basic Military Training, and reforms himself as a model recruit. However, this draws dislike and mockery from his section mates, led by the street-smart Lobang.

In an alternate timeline, Ken, Lobang and Wayang King are transferred to the Naval Diving Unit (NDU) and have to overcome obstacles and personal issues to grow as people.