"―Hey Kakeru, will you be my boyfriend?"... more>>

Kakeru is summoned to the rooftop by his school idol, Arisugawa Mirei, who suddenly asks him to become her boyfriend.
Naturally, Kakeru is perplexed.

However, Mirei wants Kakeru to become a fake boyfriend in order to keep the boys away from her.

The only person she can trust is her cousin Kakeru, whom she has been close to for a long time.
Although he has his own feelings about it, Kakeru can't ignore the fact that his cousin is in trouble, and chooses to become her lover.

―However, Kakeru had no idea.
That this relationship will make them more than just cousins. <<less

During a meal with the usual close-knit group—consisting of four members: 'Haru' (Spring), 'Natsu' (Summer), 'Aki' (Autumn), and 'Fuyu' (Winter)—Aki suddenly murmured a single phrase, "I want a childhood friend."... more>>

As a result of that utterance, ‘Natsu’, who often hangs out with ‘Aki’, undergoes a complete transformation in her behavior!?

From sharing lunch breaks to making appealing displays in swimsuits during swimming lessons!

And even going so far as to come to his house in the morning—an onslaught of full-force appeals!

‘Haruna’ and ‘Fuyuki’, a pair of close friends, get involved as well.

And thus, this summer, the relationship of the four close friends—’Haru’, ‘Natsu’, ‘Aki’, and ‘Fuyu’—underwent a significant change. <<less