In Kingdom Knight Dad, a noble royal knight returns home from his mission to reunite with his beloved daughter, Marie. The next day, during a trip to the northern forest, they come across an elf woman being attacked by a group of human raiders. Acting without hesitation, the knight saves her only to learn she is Siena, the first princess of the Elven kingdom.
Soon, Siena reveals a grim truth: her younger sister has been captured by the same men. With tensions between the human and Elven kingdoms on the brink of war, the knight embarks on a dangerous journey to rescue the kidnapped princess and prevent conflict from consuming both realms.