Because of a frightening experience three years ago, schoolboy Sata Senda has become a compulsive cleanliness freak. As he carries anti-bacterial spray and a mask as standard equipment, and doesn't allow any form of close contact, he has no friends.

Now, in the summer of sixth grade, Sata has been forced to participate in the school trip. And so, he arrives at the departure point... completely covered in a protective suit?!