Kazumi is a high school student living a fulfilling life in Hiroshima. During a visit to Peace Memorial Park with her boyfriend, she suddenly recalls childhood visits to the park with her grandmother, Kinue, for the "toro nagashi," a lantern festival to mourn loved ones who died in the war. What did Kinue say to Kazumi there? Against the backdrop of this beautiful city, this is a story about passing the message of peace on to future generations.