In a world where crime fighting is a dangerous vocation, a notorious villain named Dieter Von Cunth steals a nuclear warhead, threatening national security. The government turns to retired special operative MacGruber, a legendary yet eccentric hero renowned for his unconventional methods and improvisational skills. Despite being out of the field, MacGruber is reluctantly convinced to take on the mission to stop Von Cunth and recover the warhead. He recruits his former love interest Vicki St. Elmo and a young soldier named Dixon Piper to form a team. With a deep personal vendetta against Von Cunth for killing his fiancée, MacGruber combines absurd tactics and often disastrous plans in pursuit of his nemesis.

The team faces numerous hurdles involving elaborate yet flawed disguises and diversionary techniques that reflect MacGruber's unique style. As they navigate through Von Cunth's henchmen, they must infiltrate heavily guarded locations and decipher the villain's plans. Along the way, MacGruber's outdated skills and impulsive decisions leave the team in perilous yet comedic situations. Throughout their quest, unexpected alliances are formed as tensions rise within the team. The stakes grow higher, and every move gets them either closer or further from their goal. Despite the chaos, camaraderie develops among the trio, driving them to remain steadfast in their mission to save the day.