Kura Yami Gaaruzutouku

As women experience the many milestones of life - going on to higher education, getting a job, getting married, having children, raising children, caring for parents, and so on - and as their environments, positions, and relationships change, there are feelings they keep bottled up and unable to reveal to others.

Feelings about changing their "surname" after marriage ("Bride's Dress"), or revealing their true feelings during their first romantic relationship ("Straw Doll")... The longer these feelings are bottled up deep in their hearts, the stronger and more powerful they become, until they overflow from the "darkness."

(Source: Kadokawa, translated)