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.

Ah Boys To Men is a comedy film set in Singapore, focusing on a group of young men who are enlisted into the Singaporean military. It follows their journey as they go through the rigors of basic training and face various challenges along the way. With humor and heart, the movie explores themes of friendship, patriotism, and the trials and tribulations of serving in the military.

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.