Our Sister's Soulmate

27 year old Adachi Momoko lost both her parents in an accident when she was in third year high school. She then gave up going to college and has been working at a home centre for the past nine years while supporting her three younger brothers who are now 20, 17, and 14 year old respectively. Momoko's daily life begins to change around Halloween when she meets her love interest by chance. "Yoshioka" is a young smiley man who is slightly older than Momoko but he has a secret. Although the couple looks awkward, they are well-supported by their families, colleagues, and friends. Will Momoko be able to start a new daily life when Christmas comes?