In a fascinating blend of international diplomacy and canine adventure, a mysterious figure dressed in black arrives at the White House, carrying with him a carefully designed cage that holds a special gift from Soviet Premier Nikita Khrushchev for Caroline Kennedy. This unexpected present is none other than Pushok, a spirited stray dog from Moscow, who charms everyone he encounters with his playful antics.

The story of this furry companion, however, traces back three years earlier in 1960 Moscow. Here, a charismatic character known simply as Vova embarks on a mission to rescue dogs from the city streets. His latest target is Strelka, an adventurous terrier mix who longs to escape her mundane existence. As Vova closes in, Strelka bravely makes her escape with her loyal friend Lenny the rat by her side.

Simultaneously, a majestic Samoyed named Belka prepares for her own adventure aboard a rocket. However, her launch takes a chaotic turn when she loses control, crash-landing onto a payphone where Lenny has been busy collecting coins. This peculiar incident leads to the gathering of an eclectic group of strays: Bula, a spirited French bulldog; Mula, a lovable pug; Pirate, a sly wolf; and Strelka, who finally discovers her community within this motley crew.

As the group navigates their unfamiliar environment, they soon find themselves captured by Vova’s relentless hunt. Unexpectedly, destiny intervenes, transporting these brave canines to Baikonur, the heart of the Soviet space program training facility. There, they meet Kazbek, a seasoned German Shepherd tasked with selecting two dogs for an extraordinary mission.

As the launch day looms closer, Bula and Mula were the original picks to represent the group; however, Lenny’s determination and skill win him a spot on the mission alongside Strelka and Belka, who are selected for their outstanding training performances. Thus, this unconventional pack of heroes prepares for an adventure that will challenge their bonds and resilience.

As their thrilling journey through the cosmos comes to an end, Strelka faces a profound decision between the allure of the stars and the pull of home. Echoes of her mother’s words resonate within her: Sirius, her father, awaits among the celestial bodies. Kazbek, who had cleverly joined the mission without notice, urges Strelka to change their course, but she remains firm in her conviction. Their serene journey is suddenly interrupted by a breathtaking spectacle of meteorites hurtling toward them. The ship’s structure begins to crack under the intense assault, engulfing the vessel in flames. Undaunted, Strelka, Lenny, and Kazbek rush to the rear compartment, using their feeding formula to combat the blaze. Despite her fears, Belka bravely leaps through the flames to stabilize the rocket, steering it back to safety. As Strelka successfully puts out the fire, Kazbek confesses his heartfelt feelings for Belka. Together, the bravely bonding crew gazes in awe at the cosmic wonders, with Strelka paying tribute to Sirius.

Upon their glorious return to Earth, Strelka, Belka, and Lenny are hailed as heroes. The revelation of Kazbek’s hidden presence during the flight stirs curiosity, but the scientists involved tactfully downplay the situation to uphold the dignity of Soviet propaganda. Interestingly, Pushok shares tales of heroism to anyone willing to indulge him, while Strelka finds her way back to her mother’s loving embrace. Belka takes to the skies once more, dazzling audiences in her renewed circus act with their restored rocket. Kazbek, now content with Belka at his side, along with their fellow space-traveling canines, look forward to a future filled with joy and camaraderie.

As the film concludes, nostalgic archival footage from the Soviet space program’s canine pioneers transports the audience to a time when humans and animals worked together on groundbreaking missions, bringing their incredible story full circle.