The third installment in the Mobile Suit Gundam Thunderbolt series, "December Sky," continues the epic battle between the Principality of Zeon and the Earth Federation. This OVA (Original Video Animation) episode dives deeper into the complexities of war, character development, and the human condition, set against the backdrop of the Universal Century. The story unfolds in the year Universal Century 0079, during the height of the One Year War. The Earth Federation's Operation Star One aims to capture the Zeon asteroid base, which could potentially turn the tide of the war. Meanwhile, Lieutenant Io Flanel and his partner, Conductor Sayta, are on a mission to escort a transport carrying a new prototype mobile suit, the RX-78-2 Gundam, which could change the course of the war.

Daryl, on the other hand, embodies the zeal and conviction of a Zeon pilot. His skills and strategic thinking make him a formidable opponent. The dynamic between Io and Daryl serves as a microcosm for the larger conflict, highlighting the tragic nature of war where both sides suffer greatly. Produced by Sunrise, "December Sky" maintains the high-quality animation and attention to detail that fans of the Gundam series have come to expect. The OVA series, including "December Sky," has been praised for its return to the roots of the Gundam franchise, offering a more traditional take on the mecha genre while still innovating within it.

However, their mission takes a drastic turn when they encounter a Zeon mobile suit squadron led by the ace pilot, Daryl McNeil, in his MSM-06 Zaku II. The battle results in a devastating loss for the Federation, and Io finds himself on the run in his new Gundam, with a severely damaged ship and a dwindling crew. "December Sky" explores several themes, including the personal costs of war, the importance of camaraderie, and the struggle for survival amidst chaos. Io Flanel, once a somewhat straightforward character, is shown to grapple with the moral ambiguities of war. His interactions with Daryl McNeil add a layer of complexity to the narrative, showcasing the intense rivalry and mutual respect that can develop between enemies.