Minami-kun is my lover!?

The story

Chiyomi Horikiri (Ai Iinuma) is a warm hearted high school student. She is a member of her school's basketball team. She stays bright even in a bit complicated family composition. Her boyfriend is Hiroyuki Minami (Yusei Yagi). One day, Hiroyuki Minami suddenly shrinks in size to only 15 cm. in height. He can easily fit in the palm of someone's hand. He appears in front of his girlfriend Chiyomi Horikiri.