Retired botanist Dongho lives alone, tending to his greenhouse. He cares for wild bees, makes seed bombs, and struggles to preserve the alpine plants he brought down from Mt. Baekdu a decade ago. One day, he encounters twelve-year-old Bom, who visits his yard in search of mulberry leaves for the silkworms Bom is raising. As a bond is cultivated between them, Bom suddenly disappears, leaving only a note and a silkworm kit behind. After waiting a few days, Dong-ho sets out with a sense of foreboding to find Bom.