I Am Your Secret Letter! Record of a Covert Love Struggle

Numasuke, a shinobi in a town in Edo Japan, accepts secret letters from the Roju (elder of the town) to deliver to the young Tono (Lord of the town). Numasuke is ordered to never have the letter robbed or the contents read by others. He is then suddenly "hugged" by the elder and told to "convey this message too". Numasuke accepts that it must be an important code and conveys the "hug" to the Lord, but receives a "kiss" from the Lord in return...? What is the fate of Numasuke as the orders gradually become more radical...?! (Source: MUGENUP)