Marle accepted a request to deliver a letter to the neighboring town together with her familiar, the slime Rin. Marle and Rin thought this would be just a simple request of delivering a letter, but on the fourth day, Marle was in an absurd pinch. 「…… Help me, Rin-chan! I want to take a bath!」 Right, walking for four days without taking a bath, Marle was nearing the dangerous area as a girl. The proposal Rin had to such Marle was―― 「…… Then, would you like to enter me~?」