Ten years ago, Mika divorced her husband and raised her son Tatsuya all on her own. Facing the harsh reality of being a single mother, she worked tirelessly to support them, and thanks to her efforts, Tatsuya successfully graduated from graduate school and secured a job offer. With her role as a mother seemingly complete, Mika found herself lost, overwhelmed by a deep sense of emptiness. Then one day, Tatsuya invited her on a hot spring trip, saying it was to thank her for supporting him through graduate school. Mika accepted, and the two set off together on what would become a graduation journey. As their bond grows stronger, they step into a new beginning.