The film negates all happenings in the predecessors and explores what might have happened should the boys have been assigned to the Naval Diving Unit. The boys this time as recruits of Singapore's Naval Diving Unit (NDU). The movie offers a peek into the intensive training regime of the NDU, which have never been revealed so far. Together, the boys must survive 40 weeks of hell to become Frogmen, one of Singapore's most fearsome military units.