"Q Transformers: Kaettekita Convoy no Nazo" is a short anime series that blends the Transformers franchise with a comedic, chibi-style aesthetic. The narrative centers on the Autobots and Decepticons, who find themselves stranded on Earth after a battle damages their spaceship. The Autobots, led by Optimus Prime (referred to as Convoy in Japanese), must adapt to life on Earth while fending off the Decepticons, who continue their pursuit of energy resources to fuel their plans for domination.

The story begins with the Autobots and Decepticons crash-landing on Earth, scattering their Energon cubes across the planet. Both factions are left in a weakened state, with their bodies transformed into smaller, more comical forms due to the loss of energy. Optimus Prime, now in a diminutive size, takes on the responsibility of leading the Autobots to recover the lost Energon cubes while protecting Earth from the Decepticons' schemes. Megatron, the leader of the Decepticons, remains determined to seize the Energon cubes to restore his power and conquer the planet.

Throughout the series, the Autobots encounter various human characters, including a young boy named Akira, who becomes an ally in their mission. Akira's curiosity and resourcefulness often aid the Autobots in their battles against the Decepticons. The series features episodic adventures as the Autobots and Decepticons clash over Energon cubes, with each episode highlighting humorous and lighthearted moments alongside the action. The chibi-style animation emphasizes the comedic tone, with exaggerated expressions and slapstick humor.

Key characters include Optimus Prime, who remains a steadfast and noble leader despite his reduced size; Bumblebee, who serves as a loyal and energetic scout; and Megatron, whose relentless ambition drives the Decepticons' actions. Other notable Autobots include Ironhide and Ratchet, while the Decepticons feature Starscream, Soundwave, and other familiar faces from the Transformers universe. The interactions between the Autobots and Decepticons are marked by rivalry and comedic misunderstandings, creating a playful dynamic.

The series concludes with a climactic battle as the Autobots and Decepticons race to recover the final Energon cubes. The resolution sees the Autobots successfully thwarting Megatron's plans, ensuring the safety of Earth and restoring their own strength. The lighthearted tone and episodic structure make "Q Transformers: Kaettekita Convoy no Nazo" a unique entry in the Transformers franchise, offering a comedic take on the classic conflict between the Autobots and Decepticons.