On the remote planet of Baab, an adventurous astronaut named Scorch Supernova, alongside his more measured older brother Gary, serve in the distinguished space organization BASA. While Gary, an expert in mission support, diligently handles the responsibilities, Scorch basks in the spotlight, enjoying their thrilling interstellar escapades. Their bond faces a challenge when BASA Headquarters picks up a distress signal from Earth, referred to as the "Dark Planet" by the Baabians. Despite Gary’s strong advice against sending anyone to respond—warning of the peril that befalls any alien who steps onto human ground—Scorch disregards his brother's prudent counsel and eagerly accepts the mission.
This reckless choice ignites a fierce argument between the siblings, ultimately leading to Gary's resignation from BASA, frustrated by Scorch's bravado. He returns home to his adventurous son Kip and wife Kira, watching in anxiety as Scorch's descent to Earth is broadcasted live. As tension escalates, Gary is overwhelmed with concern for his brother's safety.
Upon arriving on the Dark Planet, Scorch finds himself in a 7-Eleven convenience store, unexpectedly ambushed by the United States Army, under the command of General William T. Shanker. The Baabian astronaut is promptly detained and taken to Area 51, deepening Gary's fears for his brother’s safety.
Determined to rescue his beloved uncle, Kip sets off on his own quest. However, Gary’s cautious instincts advise against such reckless actions, prompting him to discourage Kip's brave, yet risky, decision. That night, Gary discovers that his son has ventured out secretly, driven by his desire to save Scorch.
With time critically running out, Gary teams up with Kira to rush back to BASA Headquarters, narrowly averting a disastrous launch sequence to save their son. This unanticipated turn of events ignites a newfound sense of responsibility within Gary, compelling him to reactivate the mission sequence and take control of the situation.
Embarking on a daring rescue mission to Area 51, Gary reunites with Scorch at the same 7-Eleven where their problems began. Once again, the US Army, led by General Shanker, detains both brothers, entangling them deeper into a dangerous predicament. Gary's unexpected arrival at Shanker's office is soon interrupted by a phone call from Lena, Shanker's girlfriend, who is unaware of his ulterior motives, using their relationship solely to secure vital resources. Lena has dispatched the galaxy’s most powerful energy source, "blubonium," using Scorch's advanced robotic suit.
As Gary is taken away, he finds himself imprisoned alongside other alien captives: Doc, a small mouse-like creature; Io, a one-eyed cyclopean being; and Thurman, a sluggish entity. The primal forces of human technology have been twisted against them for Shanker’s exploiting aims, allowing him to profit immensely from their confinement.
After reuniting, Gary's frustration mounts as Scorch’s arrogance once again complicates their situation. Simultaneously, Lena captures Kira, who had remained at BASA attempting to communicate with Gary. Lena’s nefarious intention is to provide Shanker with an endless supply of blubonium. The cafeteria erupts into chaos as Gary and Scorch engage in a heated exchange, which escalates into a food fight interrupted by Shanker's entry.
When Shanker unveils the "peace shield" and the commanding blubonium, Scorch’s impulsive nature leads him to steal and shatter it, inciting Shanker’s wrath. Shanker freezes Scorch and compels Gary to mend the chaos, though this is merely a guise for his vengeful ambitions. The story unfolds revealing that Shanker’s motives are rooted in a traumatic past, specifically, the accidental destruction of his father's spaceship by a trio of grey aliens in 1947.
With the aid of his new allies, Gary manages to restore the blubonium, but Shanker betrays their agreement, freezing him too. The trapped aliens realize Shanker's true intentions to obliterate Baab using a laser weapon. Yet, Gary cleverly sabotages the machine, causing a malfunction that leads to their escape from icy confinement.
As they flee Area 51, Gary, Scorch, and their newfound allies locate Scorch's spaceship through the help of Hawk and Hammer, whom Gary had previously met at 7-Eleven. United, they navigate towards Baab, ready to confront whatever challenges are in store.
Meanwhile, on Baab, Kip acts decisively to rescue Kira from Lena, who has absconded with a vital shipment of blubonium. In a breathtaking aerial chase, Kip efficiently maneuvers his friend through a barrage of US Air Force jets. However, their escape takes a perilous turn when Shanker, now donning Scorch's robotic suit, captures their ship using a tractor beam. In a last-ditch effort, Gary and Scorch jump from the doomed vessel, reconciling in freefall just before being saved by the very grey aliens who felt remorse for Shanker’s past.
Upon uncovering Shanker's malicious plans, these extraterrestrial allies turn against him, allowing Gary the perfect opportunity to render Shanker unconscious. The authorities eventually apprehend both Lena and Shanker, while the remorseful grey aliens take Shanker away. With their conflicts resolved, Scorch returns home to Baab as a celebrated hero, graciously attributing his success to his brother Gary. To commemorate his return, Scorch weds the beloved anchorwoman Gabby Babblebrook, with Gary proudly standing by as his best man.
