"But suddenly, I had a little sister. That was the problem."

After her father's remarriage, Sachi suddenly has a new stepsister, Ayari. At first, their interactions are awkward, and very brief. However, they soon discover a shared love... of food?

Sachi soon discovers Ayari's passion for cooking, and the two step-sisters soon begin to bond over Ayari's delicious cooking, and begin to overcome the barriers that had once kept them apart. While their parents are away on their honeymoon, they learn to cope with their differences, and bond over a seemingly insignificant thing!

(Source: MyAnimeList)