Albert, who was reincarnated in another world, was aiming for a peaceful life in the Kingdom of Alexa. However, he was kidnapped by Marida, the strongest creature on earth and a demon race woman called Senki, and was wanted by the kingdom for helping her attack. Albert, who has decided to live as Marida's son-in-law in the Elancia Empire, works hard at night with Marida, who has an attractive body, and makes great achievements in domestic affairs, military affairs, and conspiracy by making use of modern knowledge. A slightly naughty harem comedy begins!