Shizuru Roji has a crush on fellow college student Nana, but he doesn't have the courage to confess. Antisocial and extremely awkward, he is only able to express his feelings for her through poetry. As if it couldn't get any worse, he meets Kokoro Maida, Nana's cousin, an odd little child that starts to call him "Mama."

As Shizuru gradually becomes attached to Kokoro, not only does he get into all kinds of mischief, he also finds himself spending more time with the girl he loves.