Kimi Arite Shiawase

Set in the Taishou era, Heigo Kurasawa, the son of a trading company president, reunites with Isamu Sakaguchi, his childhood friend from 10 years ago.

They both used to play together like brothers but now they are master and servant. Heigo is left feeling lonely because of Isamu's now unfamiliar politeness. In order to restore their past relationship, Heigo tries to treat Isamu not as a servant but as a friend instead. However, one day, Isamu discovered old love letters addressed to Heigo from a man. Heigo was upset by this discovery and when Isamu comes to hold him in his arms, he whispers...

"I will never tell anyone about this. So, please let me be the only one you open up to about this worry..."

(Source: Kadokawa, translated)