"Hibernation!" is a manga series that explores themes of isolation, survival, and human resilience in a post-apocalyptic setting. The story is set in a world where a mysterious global catastrophe has rendered the surface uninhabitable, forcing humanity to seek refuge underground. The narrative centers on a group of survivors who have taken shelter in a massive underground facility designed to sustain life for extended periods. The facility, known as the Hibernation Complex, is equipped with advanced technology that allows its inhabitants to enter a state of suspended animation, effectively "hibernating" to conserve resources and wait out the environmental crisis above.

The protagonist, a young scientist named Akira, is one of the key figures responsible for maintaining the complex's systems. Akira's expertise in biotechnology and cryogenics makes him indispensable to the survival of the group. However, as time passes, the strain of prolonged isolation begins to take its toll on the inhabitants. Tensions rise, and the fragile social order within the complex starts to unravel. Akira finds himself caught between his duty to preserve the facility and his growing concern for the mental and emotional well-being of his fellow survivors.

The plot thickens when a series of technical malfunctions threaten the stability of the complex. Akira and a small team must venture into the deeper, uncharted sections of the facility to repair critical systems. Along the way, they uncover hidden truths about the complex's origins and the true nature of the catastrophe that drove humanity underground. These revelations challenge their understanding of the world and force them to confront difficult moral and ethical questions about survival, sacrifice, and the future of humanity.

The supporting cast includes a diverse group of characters, each with their own motivations and struggles. Among them is Rina, a former engineer who becomes Akira's closest ally, and Kenta, a security officer whose rigid adherence to protocol often clashes with Akira's more pragmatic approach. The interactions between these characters drive much of the narrative, highlighting the complexities of human relationships under extreme stress.

As the story progresses, the survivors face increasingly dire challenges, both from within the complex and from the outside world. The manga delves into the psychological effects of prolonged confinement and the lengths to which people will go to protect themselves and those they care about. The narrative builds toward a climactic decision that will determine the fate of the hibernators and the future of humanity itself.