New Year's Eve. Izumi finds his mother Yuriko wandering in a park in the freezing cold. Diagnosed with dementia, her mind quickly begins to fade. Yet, for her son, memories of the mother who raised him on her own feel as vivid as the day he lived through them, especially that of the time she had disappeared from his world, which haunts him to this day. As Yuriko slips slowly into oblivion, Izumi must come to terms with losing his mother again, this time forever. In his path to finding forgiveness in himself, however, Izumi soon uncovers Yuriko's secret past and the life she lived without him.