The film opens with Singapore appearing to suffer a massive invasion, with iconic landmarks attacked and numerous civilian casualties. It is later revealed that this war is the fictitious setting of a war-based role-playing game played by Ken Chow, a rich and spoiled teenager who dreads National Service (NS). He had planned to study abroad with his girlfriend Amy, but NS stands in the way, forcing him to rethink his future. After being chided by Amy for his childish attitude, Ken vents his anger on a nearby rubbish bin, only to be apprehended by two policemen right in front of her, leaving Amy embarrassed and dismayed.
He is driven home by his father Ken's Father and confides his fears about NS to his parents. His overprotective mother Mary Chow tries to help him brainstorm ways to defer his service but ultimately fails. The Chow family sadly sends Ken off on the day of his recruitment. Thereafter, Ken and other recruits are assigned to Ninja Company (Platoon 2, Section 2), sent to their bunk, and introduced to their Platoon Sergeant Platoon Sergeant. While waiting for the mandatory haircut, Ken meets several fellow recruits: the charismatic Lobang Lobang, the highly educated Aloysius Jin Sia-lan Aloysius Jin Sia-lan, and the wary “I.P. Man” I.P. Man. Most recruits are shown making simple and goofy mistakes in their initial training, creating a rough-and-tumble but lighthearted sense of camaraderie within the group.
After two weeks of training, Ken and the others are allowed to book out for the first time. A lavish party is thrown by his family to celebrate his return, but his mood sours when he sees a photo of his girlfriend with another man. Ken angrily confronts her, and she eventually admits she has fallen for someone else and dumps him on a highway, leaving him shocked and alone. Determined to win her back, he hatches a plan to escape from Pulau Tekong, convinced that her feelings for him were merely a test.
During grueling training in hot weather, Ken begins to test his limits by cutting back on water, hoping to provoke a heat injury that would warrant ten days of medical leave. He even goes so far as to sleep under a ceiling fan after cooling himself with cold water. His condition rapidly deteriorates, and he collapses during training, landing him in a hospital. Ken's Father is alerted to his son’s critical condition while at a company meeting and rushes to the hospital, where the shock and stress contribute to a stroke that leaves him involved in a serious car crash on the way there.
Ken wakes up in a hospital, surrounded by his two sisters. He realises that his reckless actions have caused problems for many people, and he feels unable to face his father, who has survived the crash and is recuperating in a nearby ward. This moment of clarity marks a turning point for him. Awakened to reality, Ken is deemed fit enough to return to training, and the film ends at this junction, offering a glimpse of what lies ahead in his journey.
