Years after losing his beloved dog Rikimaru, Hayate dies in a freak accident and is reincarnated in a fantasy realm by a goddess. She tasks him with saving her world from impending doom and grants him the chance to reunite with his dog. The twist is that Hayate is not the hero. Rikimaru is granted the might of a legendary savior and wastes no time vanquishing evil and enjoying his zoomies, while the good-natured Hayate must navigate strange new lands and thorny political intrigue. Hayate wants to do right by the innocents of this world and pamper his lovable little pumpkin every step of the way.

The main characters are Hayate, a congenial man who acts as the strategist and diplomat, and Rikimaru, his spunky and adorable dog who possesses overwhelming combat power. The setting is a fantasy world threatened by an unknown doom, where a goddess directly intervenes by reincarnating heroes.

In the first major narrative arc, Hayate must deal with the political fallout of a dog being the world's savior. To stop the enslavement of the people of Madras, Hayate and a companion named Monica infiltrate a high society masquerade to gather intelligence. However, they run into a powerful agent of evil without Rikimaru by their side. The church hierarchy is also suspect, as an archbishop appears to be acting against the goddess's will by manufacturing blood sacrifice devices, leading to speculation about a possible evil god or a dual nature of the goddess herself.