"Skill 0 Bōkensha no Ore, Kekkon Shite Ryūō no Kishi to Naru" centers on a protagonist who is initially dismissed as weak due to his lack of combat skills, symbolized by his "Skill 0" status. Despite this, he possesses a unique ability to form contracts with powerful beings, a skill that goes unnoticed by most. His life takes a dramatic turn when he encounters a dragon king, a being of immense power and prestige. Through a series of events, the protagonist forms a contract with the dragon king, leading to a marriage pact that elevates his status and grants him the title of Dragon King's Knight.

The narrative explores the protagonist's journey as he navigates his newfound role and the responsibilities that come with it. His marriage to the dragon king not only changes his social standing but also thrusts him into a world of political intrigue, power struggles, and battles against formidable foes. The story delves into the dynamics of their relationship, blending elements of fantasy, adventure, and romance. The protagonist must balance his personal growth with the expectations placed upon him as the Dragon King's Knight, all while uncovering the true potential of his unique abilities.

Key characters include the protagonist, whose resilience and adaptability drive the story forward, and the dragon king, a powerful and enigmatic figure whose motivations and past are gradually revealed. Supporting characters, such as allies and adversaries, add depth to the narrative, creating a rich tapestry of interactions and conflicts. The manga combines action-packed sequences with moments of introspection, highlighting the protagonist's evolution from an underestimated adventurer to a respected figure in a world where strength and skill are paramount.