Thirty-year-old Natsuki Seto runs a business house without a signboard on the Inamurazaki beach in Kamakura. A radio, an old chair, an antique clock with a broken string, a faded wedding ring box - all kinds of things were delivered, and he repaired them one by one. Business is not bad, and the days are as quiet as the beach after low tide.
Until a man he hadn't seen in eight years opened the wooden door.
Kurokawa Suzu - a girl famous throughout the school in high school and the lover of his late best friend Ejima Takuma. She brought several boxes of damaged butterfly specimens and asked him if she could repair them.
The owner of those specimens was Takuma, who drove alone to Kamakura Beach when he was seventeen years old and walked into the sea holding a blue morpho butterfly.
As the specimens were opened and repaired one by one, the memories that had been sealed for eight years were peeled off frame by frame: the threesome's boyhood, the night wandering on the streets of Tokyo, the cracks that no one noticed, Takuma's too stubborn eyes when he played pool for the last time, and the line on the back of the specimen box - "I'm sorry."
Summer at the seaside comes and goes. Hiyori Asakura, a girl from the Umi House, pushed open the door with a broken surfboard in her arms; the old woman who lived at the end of the ramp brought an old thing every month; and the elementary school student who claimed to be able to see butterflies lingered in front of the store. When Seto tried to repair Ling's specimen, Ling's heart, and his own unspoken emotions, he gradually discovered that some things, perhaps, should not have been repaired from the beginning.
Purpose: Some scars in life are destined to never heal, and the real "repair" is not to return to the intact past, but to learn to carry the cracks and continue to breathe in every uncertain tomorrow.