The male protagonist, "Papa-tan" (his real name doesn't matter a bit, trust me... ), has a fairly serious crush on Mini, his cute and YOUNG-looking niece.
Our hero(?) is therefore very happy when Mini's parents send their daughter to his home for some time, but tragically he catches a nasty flu on the same day of her arrival, and he's forced to absolute bed rest.
However Mini much cares for her Papa-tan, and starts applying her personal approach to nursing...