The fireworks festival hosted at the school starts in a flash. Mizuho, whose goal that summer was to watch the fireworks with the person she loves, sprints to the pool where Kizuki is after an encouraging push from Airu. But there, she runs into Saitou-sempai, who comes back to her with his own confession! Mizuho hopes with all her heart that she can continue the relationship she's always had with Kizuki since they were children, but then she realizes her heart's filled to the brim with feelings she never knew she had. The answer she finally arrives at is...!?