When Hiyori⁠—a young girl whose deceased father taught her the joys of fishing⁠—headed out to sea for some alone time, she never thought that she would encounter another girl there.

After a while, this girl⁠—named Koharu⁠—and her end up fishing and cooking together, and they get to know each other a bit in the meantime. During their brief time together Koharu finds out that the reason Hiyori went out to sea that day was because she's hesitant towards meeting her new step family that same evening. But what a coincidence! Koharu is also meeting her new family tonight! "No. It can't be a coincidence..." Follow these two 'sisters' and their new life together!