This summer has arrived. Natsuko and her son Kenji were laughing about last year's hellish heat while eating watermelon. But once again, the air conditioner broke down, unresponsive no matter how many times they pressed the remote. Natsuko and Kenji are forced to endure another sweltering, sweat-drenched summer vacation. Struggling through the unbearable heat, they push through each day. Then, amidst their routine, a new event strikes their lives.