Kenji has a penchant for dating girls, but he struggles to land a stable relationship. While standing devastated in the rain, Kenji is sighted by his friend Kei, who quickly accompanies the drenched man with an umbrella. The two end up letting themselves dry at Kei's home—and eventually sleep together on the same futon.

Although his younger brother thinks otherwise, Kei believes that two high school students resting on the same bed is not weird at all. However, the next time they repeat the deed, romantic feelings unravel and bloom—making Kei's futon warmer than usual.