I Can't Get Married Anymore

After the incident the previous night, both Kei and Mizuho are worried. Mizuho doesn't want her secret to be revealed, but doesn't know what to do. Kei also doesn't know what he should do or how he should explain all this to his uncle. But, what will happen when Kei and Mizuho are locked in an equipment shed overnight? Even worse, what will happen when the principle finds them?!