The Handmaiden Dreams at Sunset

On Dahlia Belohr's first day as handmaiden, she simply receives one instruction: Whatever you do, do not, under any circumstances, go to the annex. But when an errand meant for another maid falls on her lap, Dahlia reluctantly finds herself walking through the very doors she was forbidden from entering and meets...him. The ghost of the annex. A permanent stain on the duke's legacy. The cursed bastard boy. What blooms is an unexpected connection that heals the pit of loneliness in both their hearts, despite the constant outside threats wanting to keep them apart.

(Source: POCKET COMICS)

Note: First released in English, with the initial eligible release in Japanese followed by Korean, making it a manga by our standards.