"Hell Contract" is an anime about a lonely man named Kaito who feels like he has nothing to live for. Desperate for companionship, he performs a ritual that summons a devil named Mephisto. Kaito wishes for Mephisto to become his girlfriend, and surprisingly, Mephisto agrees to the contract.

However, their relationship is not without challenges. God, who disapproves of the relationship between a human and a devil, intervenes and sends his angels to break the contract. Kaito and Mephisto must fight to defend their love against the forces of heaven and hell.

As the story progresses, Kaito and Mephisto's love is tested time and again, but they refuse to give up on each other. Along the way, they meet other humans and demons who are supportive of their relationship and are willing to help them.

As they fight against the obstacles in their path, Kaito and Mephisto learn more about each other and develop a deeper understanding of their own emotions. Will they be able to overcome the odds and be together forever, or will their love be torn apart by the forces of heaven and hell? Watch "Hell Contract" to find out.

Synopsis written by ChatGPT