A boy and a girl pledge lifelong friendship in a small town junior high school. The relationship between the two, who are destined to share a common dream, has passed two years without any particular development. Himari Inuzuka, a bubbly girl who has yet to find her first love, and Natsume, a plant-loving boy who enjoys flowers, still spend their days peacefully as best friends in the gardening club in the second year of high school.

"If you can't get married by the time you turn thirty, then I have to take responsibility," said Himari, prompting her brother to begin calling him 'My brother-in-law!'

However, when he reunites with his first crush, the gears of their relationship suddenly go out of sync!

I can hardly believe what a mess I've made of myself tonight. I swore I wasn't going to drink too much, but then Himari-chan kept pushing more of those strong cocktails on me, saying I needed to "loosen up." My cheeks feel so hot and flushed, and my mind is hazy. I can barely focus on anything beyond the pounding of my own heartbeat. Somehow, I've ended up back in his room at this cozy lodge, straddling his lap with my long legs draped across his thighs. I'm close enough to count every one of his eyelashes. I'm usually the composed one, the put-together Ice Queen, but tonight I'm the drunken mess pinning my first love down with my body, my ample chest heaving and pressed against his with each labored breath.