Episode 4 of "Boots" kicks off with young Ray, who is plagued by unsettling nerve-related episodes. Rather than seeking medical attention for his son, Ray's father stubbornly believes that discipline alone will cure him. To enforce this, he assigns Ray a barrage of challenging tasks. Currently, it's "swim or sink week," a grueling trial of endurance. Meanwhile, Howitt can't resist badmouthing Sullivan, accusing him of being uptight, but McKinnon swiftly shuts him down.
We soon discover that Sullivan was discharged in Guam just three months ago and now faces the urgent need to reenlist to continue his career in the Marine Corps. Fajardo, showing no mercy, refuses to grant him any further extensions and demands the necessary paperwork be completed immediately.
The recruits, on their part, are subjected to an underwater floating exercise. Those who can't endure staying submerged for extended periods are deemed failures for the day and are promptly pulled out. Ochoa, an emotionally sensitive recruit, breaks down in tears when Mason is expelled. Cameron, on the other hand, excels and shares what appears to be a meaningful moment with Nash.
Unfortunately, Ray experiences one of his episodes while underwater, forcing Sullivan to rescue him. Humiliated and frustrated by his lack of self-discipline, Ray beats himself up over the incident. Just then, Knox, the racist Drill Instructor, arrives on the scene, attempting to harass Ray. However, McKinnon intervenes and sends Knox packing.
Reluctantly, Ray is ordered to the infirmary, where he ends up befriending a female recruit who encourages him to lighten up. Meanwhile, Cameron is determined to help Ray, despite Sullivan and Nash advising him to let Ray learn how to cope with setbacks on his own. When Cameron remains steadfast, Nash steps in to brainstorm solutions with him. They conclude that fostering a rivalry with the neighboring platoon could provide Ray with a mission and help him regain his focus.
As fate would have it, Knox has been assigned to the very platoon next door, and Cameron is convinced that Ray will relish the opportunity to get back at the sergeant. That night, Cameron enlists the help of Hicks and Nash to execute a daring plan: they steal their own toilet paper and pin the blame on the neighboring platoon, setting the stage for an escalating feud.
At a nearby bar, Sullivan drowns his sorrows in alcohol and unexpectedly encounters a lawyer. His mind is in turmoil, torn between his desire to stay in the Marines—which has imbued his life with purpose—and the looming trouble in Guam that threatens to sever his ties with the corps. A flashback reveals a scene of camaraderie, where Sullivan, inebriated, gets matching tattoos with someone. Upon returning, Sullivan's mood sours as he witnesses Cameron, Hicks, and Nash callously tossing their toilet paper into the dumpster.
The next day, Sullivan observes as Cameron weaves a web of deceit. As anticipated, Cameron's lies ignite a firestorm within Ray, who is eager to reclaim their stolen toilet paper and exact retribution on the neighboring platoon. However, trouble brews in the form of a dorm inspection. Cameron shines, but Ochoa falters, his mind preoccupied and unfocused. Adding to the chaos, Hicks's pet snake escapes, only to be brutally killed by Fajardo. Once she departs, an embarrassed McKinnon vents his frustration by trashing the dormitory.
As the recruits scramble to clean up the mess, they stumble upon Nash's diary. Within its pages, Nash viciously ridicules everyone, including Cameron, whom he labels with a homophobic slur. Ray seethes with anger, while Cameron is left heartbroken.
Elsewhere, Sullivan confides in Fajardo that he cannot reenlist. Fajardo is crestfallen, for Sullivan embodies the ideal Marine. Despite her efforts to persuade him, Sullivan remains resolute. A tear escapes his eye as he salutes the flag, a poignant farewell to his military career.
That night, Ray embarks on a prank and enlists Santos as his accomplice. A flashback reveals the source of Ray's panic episodes: his father. His father confesses that he wasn't a stellar recruit, but he gave it his all and emerged as Honor Man. This revelation fuels Ray's determination to join the Marines.
Back in the present, Ray and Santos set out to find Cameron to join their mischief, but he is nowhere to be found. Nash offers his assistance, only to be brushed aside. Ochoa, overwhelmed and on the verge of崩溃 (breaking down), is consoled by Santos, who takes him along to distract him from his troubles.
Outside, Sullivan is actually meting out punishment to Cameron for his lie. He orders Cameron to retrieve all their toilet paper from the dumpster. Meanwhile, Hicks eagerly joins the prank squad, reveling in the chaos. Santos comforts Ochoa, sharing that boot camp can be a lonely experience, but they must endure it together. It's also revealed that Santos has been stuck in training for six months due to a bad knee, instead of the usual 13 weeks.
As they gather the toilet paper, Hicks and Ray act as lookouts. Ray, seizing the opportunity, decides to steal something else and dashes off. Left alone, Hicks, with a mischievous grin, proceeds to clog all the toilets in the neighboring platoon's dormitory.
Back outside, Cameron scrambles to make his case, fervently insisting on his unwavering loyalty and his earnest desire to assist Ray. Sullivan, visibly exasperated, can't believe Cameron ignored his counsel, but the latter stands his ground, declaring with a steely resolve that he'd rather face failure and depart than stand by and watch Ray crumble. This defeatist mindset only serves to ignite Sullivan's temper, who then pushes Cameron to have faith in himself and to recognize his rightful place among the Marines. Eventually, Sullivan issues a direct order for Cameron to toss the toilet paper roll, urging him to maintain the charade.
The following day, Knox is livid upon discovering that Ray has swiped the guidon flag from the neighboring platoon. Luckily, McKinnon stumbles upon it and is left thoroughly impressed. Seizing the opportunity, he offers Ray a shot at redemption, and the boy rises to the occasion, acing the swim-or-sink trial.
As Boots Episode 4 draws to a close, Sullivan heeds his own words of wisdom and signs the reenlistment papers. However, in a quiet diner nestled in town, an NCIS agent is meticulously poring over a case file that centers on Sullivan, hinting at shadows lurking beneath the surface.
