In UC 0105, twelve years have passed since the conflict known as Char's Rebellion. Despite the heroic efforts that ended that war, the Earth Federation government has sunk deeper into corruption and bureaucratic decay. The Federation's leadership actively accelerates Earth's environmental destruction while enforcing brutal policies like "Man Hunting," which forcibly deports civilians from the planet to overcrowded space colonies.

Into this oppressive world steps Hathaway Noa, the son of legendary Federation captain Bright Noa. Still haunted by the traumatic events of Char's Counterattack, including the death of the troubled young woman Quess Paraya, Hathaway has secretly assumed the identity of Mafty Navue Erin, the charismatic leader of a terrorist organization called Mafty. Operating under this alias, he pilots the advanced prototype RX-105 Xi Gundam to carry out assassinations of high-ranking Federation officials, believing that only armed resistance can purge the corrupt elite and honor the complex legacies of both Amuro Ray and Char Aznable.

Opposing him is the Earth Federation's special Circe Unit, commanded by the capable and pragmatic Colonel Kenneth Sleg. Tasked with hunting down Mafty, Kenneth pilots his own fearsome mobile suit, the RX-104FF Penelope, a machine equipped with advanced flight capabilities. The cat-and-mouse chase between Hathaway and Kenneth becomes further complicated by the arrival of Gigi Andalucia, a mysterious and wealthy young woman with an uncanny ability to see through lies. Gigi quickly becomes entangled with both men, hinting that she may already know Hathaway's true identity as Mafty.

The narrative unfolds as Hathaway arrives on Earth under the guise of a botanical researcher. After a dramatic encounter with Kenneth during a shuttle hijacking, the two develop a tense, almost friendly rivalry, unaware of each other's true roles. The central conflict escalates when Hathaway attempts to retrieve his Xi Gundam during a mid-air transfer, forcing a direct confrontation with Kenneth's Circe Unit and its ace pilot, Lane Aim, high above the planet's atmosphere.

Adapted from Yoshiyuki Tomino's 1989 novel trilogy, Hathaway's story is a direct sequel to Char's Counterattack and serves as a bridge between the earlier Universal Century conflicts and the later events of Mobile Suit Gundam Unicorn. While initially released as a theatrical film trilogy, the first film was later re-edited into a television series format, dividing its 95-minute runtime into four broadcast episodes. The work is notable for its mature themes, focusing on the cyclical nature of political violence, the psychological weight of inherited trauma, and the moral ambiguity of terrorism as a form of resistance. The film received widespread praise for its high-quality animation and realistic mechanical design, though some critics noted its darker visual palette and dense political plotting.